Review
14 April 2023
DOI 10.3389/fendo.2023.1110572
TYPE
PUBLISHED
OPEN ACCESS
EDITED BY
Ludovic Dumont,
Université de Rouen, France
REVIEWED BY
Suresh Yenugu,
University of Hyderabad, India
Singh Rajender,
Central Drug Research Institute (CSIR),
India
*CORRESPONDENCE
Arnab Banerjee
arnabb@goa.bits-pilani.ac.in
Indrashis Bhattacharya
indrashis.bhattacharya@gmail.com
†
These authors have contributed equally to
this work
SPECIALTY SECTION
This article was submitted to
Reproduction,
a section of the journal
Frontiers in Endocrinology
29 November 2022
23 March 2023
PUBLISHED 14 April 2023
RECEIVED
ACCEPTED
CITATION
Bhattacharya I, Dey S and Banerjee A
(2023) Revisiting the gonadotropic
regulation of mammalian spermatogenesis:
evolving lessons during the past decade.
Front. Endocrinol. 14:1110572.
doi: 10.3389/fendo.2023.1110572
COPYRIGHT
© 2023 Bhattacharya, Dey and Banerjee. This
is an open-access article distributed under
the terms of the Creative Commons
Attribution License (CC BY). The use,
distribution or reproduction in other
forums is permitted, provided the original
author(s) and the copyright owner(s) are
credited and that the original publication in
this journal is cited, in accordance with
accepted academic practice. No use,
distribution or reproduction is permitted
which does not comply with these terms.
Revisiting the gonadotropic
regulation of mammalian
spermatogenesis: evolving
lessons during the past decade
Indrashis Bhattacharya 1*†, Souvik Dey 2† and Arnab Banerjee 3*
1
Department of Zoology, School of Biological Science, Central University of Kerala, Kasaragod,
Kerala, India, 2 Manipal Centre for Biotherapeutics Research, Manipal Academy of Higher Education,
Manipal, Karnataka, India, 3 Department of Biological Sciences, Birla Institute of Technology and
Science (BITS) Pilani, Goa, India
Spermatogenesis is a multi-step process of male germ cell (Gc) division and
differentiation which occurs in the seminiferous tubules of the testes under the
regulation of gonadotropins – Follicle Stimulating Hormone (FSH) and
Luteinising hormone (LH). It is a highly coordinated event regulated by the
surrounding somatic testicular cells such as the Sertoli cells (Sc), Leydig cells
(Lc), and Peritubular myoid cells (PTc). FSH targets Sc and supports the expansion
and differentiation of pre-meiotic Gc, whereas, LH operates via Lc to produce
Testosterone (T), the testicular androgen. T acts on all somatic cells e.g.- Lc, PTc
and Sc, and promotes the blood-testis barrier (BTB) formation, completion of Gc
meiosis, and spermiation. Studies with hypophysectomised or chemically ablated
animal models and hypogonadal (hpg) mice supplemented with gonadotropins
to genetically manipulated mouse models have revealed the selective and
synergistic role(s) of hormones in regulating male fertility. We here have briefly
summarized the present concept of hormonal control of spermatogenesis in
rodents and primates. We also have highlighted some of the key critical questions
yet to be answered in the field of male reproductive health which might have
potential implications for infertility and contraceptive research in the future.
KEYWORDS
gonadotropins, blood-testis barrier, male fertility, spermatogenesis, infertility
1 Introduction
An alarming decline in the sperm count of men has become a global concern (1).
Spermatogenesis occurs within testicular seminiferous tubules under the regulation of
gonadotropins – Follicle Stimulating Hormone (FSH) and Luteinising hormone (LH) and
involves regulated division and differentiation of male germ cells (Gc) to sperm (2). In
mammals, it is a multi-step event that includes i) establishment of spermatogonial stem
cells (SSC) ii) self-renewal and differentiation of SSC to form spermatogonial progenitor
cells (SPC) iii) spermatogonial expansion and differentiation, iv) meiotic initiation of
Frontiers in Endocrinology
01
frontiersin.org
Bhattacharya et al.
10.3389/fendo.2023.1110572
to address the regulation of mammalian spermatogenesis by
gonadotropins from a broader developmental perspective and for
the benefit of general readers, we have cited a substantial number of
additional scientific articles in this review paper. Figure 2 is the
schematic representation of the HHT axis showing the site of sperm
production. Figure 3 represents the developmental (from the fetal
stage to adulthood) changes in plasma hormonal profiles of mice
and men. Figure 4 displays a comparative picture of the initial
critical steps in male germ cell differentiation in rodents, nonhuman primates, and humans.
differentiated spermatogonia v) meiotic progression of
spermatocytes to spermatids vi) maturation of spermatids to
spermatozoa and vii) spermiation (3). This entire process is
extremely rapid (around 35 days in mice, 52 days in rats, 46 days
in rhesus macaque and 64 days in humans) with incredible intrinsic
speed (1000 sperm/sec) (3).
The hypothalamo-hypophysial-testicular axis (HHT axis) is a
three-tier neuro-endocrine circuit with hierarchical regulatory
cascades (both stimulatory and inhibitory feedback loops) (4).
Under the influence of hypothalamic KNDy (K= Kisspeptin, N=
Neurokinin B and Dy = Dynorphin) neurons, specific nuclei located
at mediobasal/preoptic/arcuate/infundibular area synthesize and
release decapeptide GnRH in a pulsatile manner (5). The GnRH
further stimulates pituitary-gonadotrophs to secrete gonadotropins
(LH and FSH). The differential pulse frequency and amplitude of
GnRH, selectively augments either LH or FSH (high and low
frequencies favor LH and FSH respectively) release (5). LH acts
on the interstitial Leydig cells (Lc) to produce the testicular
androgen—testosterone (T) (6). Sertoli cells (Sc) are the major
component of the seminiferous tubules that express the receptors
for both FSH (FSH receptor, FSH-R) as well as T (androgen
receptor, AR) and provide critical micro-environment for Gc
nourishment and differentiation (6). Sc-produced inhibin and Lcgenerated T selectively suppress the release of FSH from the
pituitary and GnRH from the hypothalamus respectively (4–6).
Within twenty years of their identification (7), clinical cases of
familial hypogonadism due to isolated gonadotropic deficiency
started to get reported frequently (8, 9). In 1971, GnRH
(previously known as LHRH) was purified and subsequently got
recognized for the Nobel Prize in 1977 (10–12). The same year, a
naturally occurring mutation in GnRH [termed as hypogonadal
(hpg)] was reported in mice confirming the absolute necessity of
gonadotropins in gonadal functions and gametogenesis (13).
During the 1980s to mid-1990s classical endocrinological studies
employed hypophysectomised or GnRH-depleted (either
immunologically or pharmacologically) animal models
supplemented with purified or recombinant gonadotropins (either
alone or in combination) indicating the probable functions of FSH
and LH (via T) in spermatogenesis (14–17). From the late 1990s, the
success of genetically manipulated mouse models (both gain-infunction or knockout strategies) has further revealed the selective
and synergistic role(s) of FSH and LH in regulating male fertility
(18–21). This article briefly discusses the critical gonadotropic
control of spermatogenesis. We further highlight currently
unanswered areas in gonadotropin biology having potential
implications on male infertility and contraceptive research.
We have prepared a PRISMA flow diagram (Figure 1) to
systematically document the advancement of knowledge in the
role of gonadotrophic hormones in the regulation of
spermatogenesis in mammals. The flow chart is self-explanatory;
in brief, we looked into the PubMed® database for papers dealing
with the topic in hand in the last decade. We only included original
research papers, whose full text is deposited in the said database and
concerns studies performed only on mammalian species. Thus, we
narrowed down the total number of cited articles to 64 from 752
with the help of imposed inclusion and exclusion criteria. However,
Frontiers in Endocrinology
2 FSH
2.1 FSH-receptor: Mode of signalling
FSH is a glycoprotein hormone having disulfide-rich
heterodimers, a common a subunit (sharing with TSH and LH),
and a unique b subunit. Evolving pieces of evidence suggest that
pituitary-derived activins are the primary stimulators of FSH
generation by gonadotrope cells. Activins control transcription of
the FSH component gene (Fshb) in vitro via SMAD3, SMAD4, and
FOXL2 (22–25). FSH acts on Sc via FSH-R (Figure 2), a G proteincoupled receptor (GPCR), which transmits its signal by recruiting
the intracellular GTP binding proteins (G-proteins, either
stimulatory Gas or inhibitory Gai) associated with it (26). Dual
coupling of Gas or Gai to FSH-R differentially modulates the
activity of adenylyl cyclase (AC) to regulate FSH-induced cAMP
production within Sc (26). The concentration of cAMP
subsequently directs the multiple downstream signaling cascades
such as canonical Protein Kinase A (PKA) or other (PKC, PI3K,
Akt/PKB, and ERK1/ERK2) pathways highlighting the pleiotropic
effects of FSH in Sc (26). The robust cAMP response in Sc results in
the activation of PKA which in turn phosphorylates cAMP
Response Element Binding protein (CREB) to induce the
transcription of genes such as Stem cell factor (SCF), Glial cell
line-derived neurotrophic factor (Gdnf), Androgen binding protein
(Abp), Kruppel-like factor 4 (Klf4), Transferrin etc, that play a
critical role in Gc differentiation (6, 26–30).
2.2 Developmental expression profile
In rats, FSH-R is first detected at E14.5 [embryonic age in days
(E)], whereas the fetal plasma FSH concentration rises from E 19.521, peaks at P5 [post-natal age in days (P)], then substantially drops
during P15-20, finally recovered to a steady state by P40-50 (31, 32);
similar events occur in mice (Figures 3A, C). On the other hand,
FSH is uniformly detectable in human fetal circulation from 12-18
week of gestation (WG), peaks during 20-22 WG and then
gradually declines in term pregnancy (Figures 3B, D) (33, 34),
whereas specific binding of FSH is observed in human and rhesus
monkey (Macaca mulata) testes during 8–16 and 19–22 WG,
respectively (35, 36). In post-natal life, FSH concentration first
raises upto the adult range within a week of parturition and stays
stable till 4-6 months, then declines and gets undetectable during
02
frontiersin.org
Bhattacharya et al.
10.3389/fendo.2023.1110572
FIGURE 1
PRISMA flow diagram of selection of articles published in last decade related to gonadotropic regulation of spermatogenesis in mammals.
unlike puberty, FSH induced cAMP production is limited during
infancy in both rats (27, 28) and rhesus monkeys (29, 30) and
therefore Sc fails to support robust Gc differentiation at younger
ages despite being exposed to sufficiently high levels of FSH and
FSH-R (27–29). Unlike pubertal cells, diminished plasma
membrane localization of FSH-R protein in rats (27) and limited
expression of Gas protein in monkeys are considered to be the
underlie causes of such poor cAMP response by FSH in infant
Sc (29).
the juvenile period prior to its re-elevation at puberty (4, 5).
Although circulatory FSH levels remain relatively constant in
adult men and rats (4, 5), the expression pattern of FSH-R
cyclically changes in a stage-specific manner, maximal during
stages XIII–II and minimal at VII–VIII (37). FSH has been
shown to suppress FSH-R transcription at 6-8 hr (38) in cultured
Sc and subsequently gets recovered by FSH at 24-48 hr (39).
2.3 Mode of function
2.4 Action in rodents
In utero life, FSH has been shown to induce Sc proliferation and
augments AMH (Anti Müllerian Hormone) production in both
rodents (40) and primates (41) and this fetal expansion of the Sc
population critically regulates the maximal spermatogenic output in
adult testes (42–45). Such FSH-driven Sc proliferation gets
continued in neonatal (upto P15) rats and infant primates (upto
3-6 months) and ceases with functional maturation of Sc during
pubertal development (27–30). It is interesting to note here that
Frontiers in Endocrinology
In hypophysectomised or GnRH depleted (via pharmacological
or immunological inhibition) rats, administrations of FSH alone
show partial spermatogenic restoration (46, 47). For example, FSH
replacement in GnRH antagonist-treated rats significantly rescues
spermatogonia B and early spermatocytes (48). Immunoneutralization of FSH in post-natal rats indicates FSH promotes
03
frontiersin.org
Bhattacharya et al.
10.3389/fendo.2023.1110572
FIGURE 2
Hormonal control of spermatogenesis by the hypothalamo-hypophysial-testicular axis through a three-tier neuro-endocrine circuit. Curved blue
arrows indicate a renewal of the cells; solid and dotted colored arrows denote the primary action and feedback action of the hormones. A-R,
androgen receptor; BTB, blood-testis barrier; FSH, follicle stimulating hormone; FSH-R, FSH receptor; LH, luteinizing hormone; LH-R, LH receptor;
T, testosterone. Only one seminiferous tubule has been shown to contain the germ cells; for others, it has been intentionally not shown, only to
keep the figure less complicated for viewing of the readers.
A
B
C
D
FIGURE 3
Changes in the endocrinal profiles in the course of the development of male gonads from the fetal stages to adulthood. (A, B): Comparison of
gonadal cell numbers in rodents and humans. (C, D): Comparison of hormonal levels in rodents and humans. ALc, adult Leydig cell; AMH, antiMullerian hormone; FLc, fetal Leydig cell; FSH, follicle stimulating hormone; GnRH, gonadotropin-releasing hormone; LH, luteinizing hormone; NLc,
neonatal Leydig cell; Sc, Sertoli cell; T, testosterone.
Frontiers in Endocrinology
04
frontiersin.org
Bhattacharya et al.
10.3389/fendo.2023.1110572
FIGURE 4
Comparison of stages of testicular development of the male germ cells among rodents, non-human primates, and humans. Note that the stem cell
property differs between rodents and primates; the number of detectable stages of differentiation of the male germ cells varies significantly among
all these three groups of animals. Colored curved arrows denote cell renewal; red question marks indicate unknown pathway.
FSH-R* shown to rescue male fertility in LH-Receptor (LH-R)
KO mice with a complete absence of testicular androgens (due to
exogenous flutamide treatment) (59).
Sc proliferation and Gc survival in neonatal age, whereas premeiotic Gc differentiation in pubertal age (49). Exogenous
administration of FSH alone in pre-pubertal hpg mice fails to
induce sperm production (50). Similarly, pituitary independent
transgenic expression of human (h) FSH (51) or mutated [at
Asp567Gly and constitutively active (capable of FSH independent
cAMP production)] h-FSH-R (h-FSH-R*) (52) in male hpg mouse
leads to incomplete meiotic progression. Furthermore, although hFSH-R* over-expression augments proliferation/development of Sc/
pre or early meiotic Gc in wild-type testes (53) this hyper-active
receptor fails to maintain normal spermatogenesis during
experimental deprivation of gonadotropins (54). However, overexpression of h-FSH-R* shows LH-independent steroidogenic
activity (55). Notably, over-expression of FSH-Rs [either h-FSHR* (along with normal h-FSH-R) or another hyper-mutated (at Asp580-His, constitutively active (capable of FSH independent cAMP
productive) mouse (m) FSH-R (m-FSH-R*)] do not affect normal
spermatogenic maintenance (55). Finally, both FSH or FSH-R
Knock-out (KO) mice demonstrate reduced testis size with
reduced numbers of Sc and Gc (spermatogonia, spermatocytes
and round spermatids) leading to sub-fertility (56–58) concluding
dispensable role of FSH in rodents. However, this dogma has
recently been challenged as the expression of hyper-active m-
Frontiers in Endocrinology
2.5 Action in primates
FSH has been shown to be mitogenic for Sc and induce early
differentiation in spermatogonia A in rhesus and cynomolgus
monkeys (long-tailed macaque; Macaca fascicularis) (15–17).
However, five finish men with an inactivating mutation in FSH-R
have been reported to have variable degrees of spermatogenic
failure without complete loss of fertility (60). In multiple
hypogonadotropic hypogonadal clinical studies (61–64) and/or
experimentally induced and/or gonadotropin deficient nonhuman primates (65–68), supplementations of FSH alone
(independent of LH/T) results to limited spermatogenic recovery
without appearance of either elongated spermatid or spermatozoa.
FSH has been shown to regulate the number of pachytene
spermatocytes in adult men (69). These reports suggest that like
rodents, FSH plays only a supportive role in regulating male fertility
in men. However, there are substantial contradictory reports
available in men indicating an absolute requirement of FSH for
05
frontiersin.org
Bhattacharya et al.
10.3389/fendo.2023.1110572
15-21) gradually get replaced by T producing ALc (85, 86). FLc also
secretes INSL3, a member of the insulin-relaxin family of peptides
that acts on the body through the G-protein-coupled receptor
relaxin/insulin-like family peptide receptor 2 (RXFP2). Missense
mutations or ablation of Insl3 or Rxfp2 causes cryptorchidism
leading to azoospermia (87, 88). However, unlike rodents,
primate Lc shows a triphasic developmental pattern (83–86). In
human, FLc peak during 12-14 WG (83) and subsequently get
dedifferentiated by the end of the second trimester and is replaced
by a unique population of neonatal-Lc (NLc) just during/after birth
which persist for first 4-6 months of infantile age, when the HHT
axis remains active (89). During the onset of juvenile period
(inactivation of the HHT axis) massive involution occurs in the
NLc population and finally ALc population originates from the
dedifferentiating NLc population during puberty (83).
sperm production. For example, hCG-mediated suppression of
circulatory FSH in adult men results into poor sperm counts,
with one individual developing complete azoospermia, which later
gets recovered by FSH supplementation alone (70). Similarly, a
hypophysectomized man with complete gonadotropin deficiency
fathered three children having h-FSH-R* (71). Finally, complete
infertility has been observed in men lacking normal circulating FSH
due to mutated FSH-b (72–74). Furthermore, two cases of isolated
FSH deficiency with normal FSH-b gene and usual LH/T levels
[first, two young men having moderate testicular hypotrophy (75,
76), second, a 19 years old boy being homozygous for a novel silent
polymorphism (G/T substitution) in FSH-b promoter (77),] show
severe sperm abnormalities to complete azoospermia respectively.
Intriguingly, immuno-neutralization of circulatory FSH shows
acute spermatogenic abnormalities in both bonnet monkeys
(Macaca radiata) (78) and men (79) suggesting FSH vaccination
as a promising male contraceptive strategy (80). Taken together, the
critical contribution of FSH in regulating primate spermatogenesis
is still currently disputed (15, 17, 81, 82).
3.3 Signalling and critical function
Like FSH-R, LH-R/LHCG-R is also a GPCR that recruits
cAMP-dependent PKA pathway to induce the expression and
activation of steroidogenic acute regulatory protein (STAR) at the
outer mitochondrial membrane of ALc leading to cholesterol
trafficking for initiation of steroidogenesis and eventually
biosynthesize T (90). However, despite being responsive towards
LH signal, FLc of both rodents and primates are independent of fetal
LH action (83). FLc number or external genitalia remain unaffected
in hpg (13), LH-RKO (91), LH-bKO (92) and ARKO (93, 94) adult
male mice suggesting murine FLc are functionally independent of
LH or T. In contrast, although patients having LH-b mutations
show normal masculinized development (95–99), LHCG-R
mutations lead to pseudo-hermaphroditism (100) indicating
definite role of hCG on FLc functioning in men. However, in
both the species LH is absolutely required for ALc function (83)
as evident from various mouse models [hpg (13), LH-RKO (91),
LH-bKO (92) and ARKO (93, 94)], etc and mutations in human
LH-b/LHCGR genes resulting masculinized fetus but compromised
pubertal development and complete azoospermia due to total
absence of functional pituitary LH and testicular T (100). It is
interesting to note here that fertility can be restored in men with
isolated LH deficiency due to mutations in the LHb gene by longterm hCG supplementations within the critical “window of
testicular susceptibility” during pubertal development (101).
Stimulation of LH (resulting T) in rhesus and cynomolgus
monkeys leads to spermatogonial differentiation and initiation of
Gc meiosis without insignificant rise in Sc number (15, 17, 102–
105). LH/hCG (or T) mediated absolute recovery of
spermatogenesis has been demonstrated in gonadotropin
withdrawal models (either by hypophysectomy or treatment of
GnRH receptor antagonist or active immunization against GnRH)
in adult rodents (106–111), men (64, 112, 113) and non-human
primates (114–118). Exogenous supplementations of T or LH/hCG
alone have been shown to induce complete spermatogenesis in
immature hpg mice (119, 120) or natural or induced hypogonadal
men (121, 122). Genetic ablations of LH-b or LH-R in mice further
show cryptorchid testes with spermatogenic arrest and male
3 LH
3.1 Developmental expression profile
LH binds to LH-R expressed by interstitial Lc and indirectly
exerts its actions on spermatogenesis through T–AR interaction via
regulating Sc functions (Figure 2) (6, 82). In rats, fetal plasma LH
concentration gets elevated from E 18- 21, then rises at P5-7, further
gets reduced during P 20-25, rises again by P35 to peak at P60 and
remains constant thereafter throughout adulthood prior to aging (P
400-500) (31, 32). In humans, pituitary LH is measurable from 1218 WG (which is around 10-fold lower than placental hCG), peaks
during 20-22 WG and then gradually decline in term pregnancy
(Figures 3B, D) (33, 34). However, such a pattern remains
inconsistent with the corresponding T profile which peaks during
12-14 WG and then drops during the second trimester
corroborating with placental hCG (83). In post-natal life, LH
concentration first raises upto the adult range within a week of
parturition and then stays stable till 4-6 months, subsequently gets
undetectable during the juvenile period, and finally shows the
pubertal elevation by reaching its maximal range (4, 5).
3.2 Target cells
C l a s s i c a l hi s t o l o g ic al s t u d i e s h a v e i d e n t i fi e d t w o
developmentally diverse populations of Lc e.g.- fetal (FLc) and
adult (ALc) (83). FLc originate from coelomic epithelium and notch
active Nestin-positive perivascular cells located at the gonad–
mesonephros borders, and get specified as Nr5a1 or Ad4BP/SF-1
expressing cells by E 12.5 in fetal mouse testes (84). These cells
produce androstenedione (precursor of T, due to lack of HSD17b3
enzyme) and play a critical role in initial virilization and patterning
of the male external genitalia (84). However, in neonatal (P 5-15)
testis, FLc undergo massive dedifferentiation and during puberty (P
Frontiers in Endocrinology
06
frontiersin.org
Bhattacharya et al.
10.3389/fendo.2023.1110572
to specific DNA sequences having Androgen Response Elements
(ARE) and initiates the androgen-dependent transcriptional events
e.g. Rhox5 expression (155). However, in a non-classical pathway, T
gets coupled with membrane-bound AR and triggers the binding of
the proline-rich region of AR with the SH3 domain of membrane
bound SRC kinase leading to stimulation of EGF receptor and
subsequently activates MAP (RAF, MEK, ERK) kinase or CREB
cascade inducing several genes which lack typical AREs on their
promoters e.g. Ldha, Claudin11, etc (155). In vitro studies show that
T regulates spermiation via a non-classical pathway (155), however,
in vivo studies suggest that classical pathway is most crucial for
meiotic completion of Gc and fertility (159).
infertility (91, 92). Human patients having inactivated LHCG-R or
LH-b frequently show pseudohermaphroditism and cryptorchidism
with Lc hypoplasia and spermatogenic arrest (123–132).
Interestingly, a unique homozygous deletion on exon 10 in
LHCG-R has been reported in an azoospermic man having
normal phenotype with diminished LH signaling (but not
towards hCG) indicating higher potency of hCG on ALc (123). In
contrast, activating mutations in LH-b or LHCG-R were shown to
be associated with precocious puberty and Lc hyperplasia (133–
148). Such precocious puberty with Lc hyperplasia followed by
infertility has been observed in mice over-expressing hyper-active
(Asp582Gly) LH-R (149). However, spermatogenesis has been
reported in a man with a splice-mutation (homozygous point
mutation G to A at -1 position of intron-10 to exon-11 junction)
in LHCG-R with severe loss of T production (150). A more
surprising study has been reported in a 43 years old man with a
homozygous deletion of nine bases in LHb gene generating a
deletion of amino acids from 10 to 12 (His, Pro, Ile) in the
amino-terminal critical for conformational changes leading to
undetectable LH (high FSH) with very low T (151). Paradoxically,
this isolated LH deficiency case eventually shows sub-optimal but
spontaneous spermatogenesis (151). It is important here to note
that, despite high (20-100 fold) intra-testicular T (IIT)
concentration has been considered to be critical for
spermatogenic initiation (152, 153), low levels of T are sufficient
to drive spermatogenic maintenance as evident by spontaneous
spermatogenesis in LH-RKO mice at 12 months of age (154).
4 Synergy between FSH and LH/T
A productive synergy between FSH and LH (via T) has been
observed in regulating maximal spermatogenic output (6, 14, 16,
17). For example, combined FSH and LH/hCG/T stimulations show
better spermatogenic restoration than independent hormonal
treatment in induced GnRH-depleted adult rats (16, 111) or
primates (172–174). Patients suffering from hypogonadotropic
hypogonadism show appreciable testicular maturation with
sufficient Gc differentiation with combined FSH and hCG
administrations (175–177). Pulsatile stimulations of LH and FSH
together for only 11 days demonstrate enhanced Gc differentiation
(upto spermatogonia B and primary spermatocytes) as compared to
independent treatment of either LH or FSH in juvenile male
monkeys (104). Moreover, T augments genes involved in FSH
signalling pathway (e.g.- FSH-R, Gas and Ric8b etc) resulting in
elevated cAMP response in pubertal monkey Sc (178). These
reports suggest that a coordinated network of FSH and T
signalling in Sc facilitate the timely onset of the first
spermatogenic wave in pubertal primates (14, 16, 17). Finally,
spermatogenesis in Sc specific isolated or double (both FSH-R
and AR) knockout mice gets affected more severely than single
genetic ablation (either FSH-R or ARKO/SCARKO) confirming a
dynamic synchronization between FSH and T action regulating the
spermatogenic output thus male fertility (179–181)
3.4 Mode of T action
LH operates spermatogenic regulations through testicular
androgen T and AR (155). T is essential for suppression of AMH
(156, 157), pubertal maturation of testicular somatic cells (e.g.- PTc,
Sc, Lc in developmental order) (2), the establishment of Blood-testis
barrier (BTB) (158), meiotic progression of Gc and spermiation
(159). The free titer of T depends upon the extent of the presence of
sex hormone-binding globulin (SHBG) which binds to T with
strong affinit y; thus, SBHG regulates the process of
spermatogenesis by controlling the serum concentration of
biologically active T (160, 161). The absolute requirement of T on
male fertility has been confirmed from ARKO (ubiquitously lacking
AR) mice (93, 94). Despite most of the somatic testicular cells (Sc,
PTc, Lc etc) express AR, Gc do not have functional AR (2, 3). Cellspecific selective ablation of AR [Sc specific i.e. SCARKO (162–164),
Lc specific i.e. LcARKO (165, 166), PTc specific i.e. PTARKO (167,
168) or Gc specific i.e. GcARKO (169, 170)] demonstrated that AR
expressed by Sc plays a pivotal role in the progression of Gc meiosis
(20, 21, 155). Furthermore, the crossing of hpg mice with ARKO or
SCARKO mice followed by T/5a- dihydrotestosterone (DHT)
supplementation confirmed the critical significance of Scmediated AR signaling in spermatogenesis (171). The transition
of round to elongated spermatid is fully dependent on T action
transmitted via Sc (159).
In Sc, AR signals via both classical and non-classical manner
(155). In the classical pathway, T (or 5a-DHT) activated AR binds
Frontiers in Endocrinology
5 Conclusion and future directions
For the past 50 years, various laboratories across the globe have
significantly contributed in revealing the gonadotropic regulation of
spermatogenesis (16, 17) with potential clinical implications (182,
183). Table 1 describes the critical role(s) of FSH and LH (T) in
spermatogenesis, whereas Table 2 highlights the significant
discoveries/advancements accomplished during past five decades
in a chronological order.
In summary, hypothalamic KNDy neurons induce GnRH
discharge which further stimulates the secretion of gonadotropins
(FSH and LH) from pituitary. High and low pulse frequencies of
GnRH selectively favor either LH or FSH release. Multiple
experimental/natural models (e.g.- hypophysectomised or
pharmacological/immunological deprivation of GnRH, hpg mice
07
frontiersin.org
Bhattacharya et al.
10.3389/fendo.2023.1110572
TABLE 1 Critical roles of FSH and LH in the regulation of mammalian spermatogenesis.
Gene
and
Protein
Name
FSH
LH
(via T)
Receptor
Target Cells
Major Functions
FSH-R
Testicular Sertoli cells
(Sc), Bone, and
Epididymis.
i) Fetal and pre-pubertal expansion of Sc population to set the upper limit of sperm production.
ii) Augmenting expression of SCF, GDNF, BMP4, Cyp19 Aromatase, FGF2 etc in Sc to regulate
the induction of the proliferation/differentiation of undifferentiated spermatogonial cells.
iii) Survival signal for proliferating pre- meiotic Gc.
iv) Proliferation of Epididymal cells.
Testicular Leydig cells
(Lc)
i) Production of testicular androgen, T.
ii) Induction of virilization of male genital tract from embryonic Wolffian duct.
iii) Driving suppression of AMH in pubertal Sc.
iv) Promoting functional maturation of Sc during pubertal development.
v) Establishment of BTB.
vi) Meiotic progression of developing Gc, transforming round spermatid to elongated spermatid.
vii) Regulating spermiogenesis and spermiation.
viii) Controlling male sex drive/libido.
Common a
Specific b
Common a
Specific b
LH-R
Note that various target cells of each of these hormones are affected differentially by it.
TABLE 2 Chronological representation of the pioneering progress in gonadotropin biology during past decades.
Duration/
Decade
Main Model used
Aim and Experimental setup
Significant Outcome
Key Review
References
1920-1950s
Equine/Ovine/Porcine/
Rodents species and human
patients/clinical case studies
Isolation/Characterization of gonadotropins
Identifications of FSH/PMSG/
LH/hCG etc
1960s
Ovine/Porcine/Rodents,
species and human patients/
clinical case studies.
Isolation/Characterization of LHRH (GnRH) and
gonadotropins
i) Purification of GnRH,
ii) Establishment of RIA to
measure serum hormonal
profiles
1970s
i) Rodents/Non-human
primates/Human,
ii) Hypogonadal boys or men/
clinical male patients
i) Withdrawal effects of FSH and LH after
hypophysectomy, or GnRH antagonist treatment, GnRH
immuno- neutralization
ii) Initiation of spermatogenesis by FSH/LH (purified) in
clinical hypogonagal boys/men.
i) Serum hormonal profiling
from fetal stage to adulthood
ii) Effect of hormones in
testicular function and Gc
development
ii) Discovery of natural
mutations like hpg and tfm
mice
1980s-mid
1990s
i) Rodents/Non-human
primates/Human,
ii) Hypogonadal boys or men/
clinical male patients
i) Withdrawal effects of FSH and LH after
hypophysectomy, or GnRH antagonist treatment, GnRH
immune-neutralization, FSH immunoneutralization/
vaccination, T mediated suppression of GnRH
.
ii) Restoration of spermatogenesis after GnRH/FSH/T
withdrawal by exogenous supplementations of FSH/LH/
hCG (purified/recombinant) either alone or in combination
iii) Initiation of spermatogenesis by FSH/LH/hCG
(purified/recombinant) in hpg mouse or clinical
hypogonadal men
iv) Pulsatile stimulation of GnRH in male juvenile monkeys
for induction of synchronized precocious puberty
v) Culturing Sc and Lc for evaluating FSH/T and LH
induced downstream signalling events/gene transcriptions
i) Independent and/or
synergistic effects of hormones
in testicular function and Gc
development
ii) FSH essential for
maintaining Sc & pre-meiotic
Gc numbers
iii) LH/hCG (via T) critical for
complete recovery of male
fertility
iv) productive synergy between
FSH and T in optimizing
spermatogenic output
v) Identifications of inactivating
or hyper-active mutations in
FSH-R/LHCG-R genes in
human/mouse.
vi) FSH-R, LH-R and ARmediated signalling cascades in
Sc and Lc
(6, 14–17, 89, 131,
182, 183)
Mid 1990s2020
i) Rodents/Non-human
primates, Human
ii) Hypogonadal boys or men/
clinical male patients
iii) Boys and men with either
i) Pusatile stimulation of GnRH or FSH/LH in male
juvenile/adult monkeys for induction of synchronized
precocious puberty or Gc differentiation
ii) Culturing Sc and Lc and evaluating FSH/T and LH
induced downstream signalling events/gene transcription
i) Independent and/or
synergistic effects of FSH and
LH (T) in testicular function
and Gc development
ii) Identification of FSH and T
(6, 17–21, 26–30,
80, 81, 83, 85, 86,
89, 131, 159–171,
181, 184–186)
(7)
(7, 12)
( 4, 5, 13–17, 89,
182, 183)
(Continued)
Frontiers in Endocrinology
08
frontiersin.org
Bhattacharya et al.
10.3389/fendo.2023.1110572
TABLE 2 Continued
Duration/
Decade
Main Model used
Aim and Experimental setup
Significant Outcome
inactivating or hyper-active
mutations in either FSH-R or
LHCG genes
iii) Whole or cell type-specific knockout mice models of
FSH-b. LH-b, FSH-R, LH-R, AR, etc.
iv) Investigating FSH or LH/T inducible/responsive genes
in Sc/Lc culture or in knockout mice models for FSH-R/AR
etc by Microarray/RNA-seq analyses
v) Single-cell transcriptomics in different testicular cells
responsive genes in Sc and Gc
development
iii) Redundancy of FSH in
rodent spermatogenic
progression/completion/
spermiogenesis
iv) Critical role of FSH in
human spermatogenesis
v) Absolute requirement of T in
Gc meiosis via Sc
vi) Identifications of
inactivating or hyper-active
mutations in FSH-R/LHCG-R
genes in human/mouse.
vii) Genomic and Non-genomic
mode of actions of T in Sc
critical for male fertility
viii) Cell type specific unique
transcriptional profiling in
different stages differentiating
Gc,
ix) Differential gene expression
during phases of Sc and Lc
maturation
x) Discoveries of hormoneresponsive novel putative
noncoding RNAs regulating
male fertility or infertility
multiple in vitro (184) and in vivo (185) studies. Future studies
utilizing a cutting-edge single-cell transcriptomics approach are
required to identify and investigate such putative gonadotropic
inducible genes crucial for regulating male fertility with the
following probable objectives/outcomes: significant advancement
in classifying and curing idiopathic male infertility, bioengineering
of fertilizable spermatozoa ex vivo, and sustainable development of
potential male contraceptive targets (186, 188).
or hypogonadal men), inactivating or hyper-activating mutations in
FSH-R/LHCG-R in men, murine genetic KOs collectively show the
crucial role of FSH and LH (via T) in spermatogenic development
and maintenance. In rodents, FSH essentially supports Sc
proliferation and survival, division, and differentiation of premeiotic Gc, but fails independently to direct the completion of
spermatogenesis. However, the sole role of FSH still remains
controversial in men. On the other hand, LH (via T) founds to be
indispensable for regulating male fertility in both species and Scmediated AR signaling found to be is most critical for the transition
of round to elongated spermatids and the induction of spermiation.
A productive synergy between FSH and T has been established to
optimize the spermatogenic capacity both qualitatively and
quantitatively. A recent report indicated the presence of a
mesenchymal transcription factor (Tcf) 21 positive interstitial
progenitor population acting as a potential reservoir during
injury-induced ALc regeneration (187).
However, despite such extensive information generated during
past decades translational progress in terms of clinical success has
not been achieved yet in the field of gonadotropin biology toward
treating infertility in men or developing reversal male
contraceptives (1). This is largely due to limited numbers of
hormone [FSH and LH (T)]-responsive genes identified so far
with defining impact on spermatogenesis identified till date from
Frontiers in Endocrinology
Key Review
References
Author contributions
IB conceived the idea and designed and prepared the initial
draft. SD prepared the figures, revised the manuscript and
generated the final form with inputs from AB. All authors
contributed to the article and approved the submitted version.
Funding
IB acknowledges the financial support from the University
Grants Commission (F.30104/2015BSR) and Department of
Science and Technology (ECR/2018/000868) New Delhi and Core
fund to Dept. of Zoology, Central University of Kerala, Kasaragod,
09
frontiersin.org
Bhattacharya et al.
10.3389/fendo.2023.1110572
Conflict of interest
Kerala, India. SD appreciates the support obtained from Prof.
Raviraja NS, Co-ordinator, Manipal Centre for Biotherapeutics
Research, MAHE, Manipal. SD thanks DBT (BT/RLF/Re-entry/
08/2019), New Delhi, India, for financial assistance. AB appreciates
financial support received from DBT (BT/PR32910/MED/97/473/
2020). However, the funder was not involved in the study design,
collection, analysis, interpretation of data, or writing of this review.
The authors declare that the research was conducted in the
absence of any commercial or financial relationships that could be
construed as a potential conflict of interest.
Publisher’s note
Acknowledgments
All claims expressed in this article are solely those of the authors
and do not necessarily represent those of their affiliated organizations,
or those of the publisher, the editors and the reviewers. Any product
that may be evaluated in this article, or claim that may be made by its
manufacturer, is not guaranteed or endorsed by the publisher.
SD appreciates the support obtained from Prof. Raviraja NS,
Co-ordinator, Manipal Centre for Biotherapeutics Research,
MAHE, Manipal.
References
1. Agarwal A, Baskaran S, Parekh N, Cho CL, Henkel R, Vij S, et al. Male Infertility.
Lancet (2021) 397(10271):319–33.
21. Wang RS, Yeh S, Tzeng CR, Chang C. Androgen receptor roles in
spermatogenesis and fertility: lessons from testicular cell-specific androgen receptor
knockout mice. Endocr Rev (2009) 30(2):119–32. doi: 10.1210/er.2008-0025
2. Sharpe RM. Regulation of spermatogenesis. In: Knobil E, Neil JD, editors. The
physiology of reproduction. New York: NY:Raven Press (1994). p. 1363–434.
22. Li Y, Schang G, Wang Y, Zhou X, Levasseur A, Boyer A, et al. Conditional
deletion of FOXL2 and SMAD4 in gonadotropes of adult mice causes isolated FSH
deficiency. Endocrinology (2018) 159(7):2641–55. doi: 10.1210/en.2018-00100
3. Griswold MD. Spermatogenesis: The commitment to meiosis. Physiol Rev (2016)
96(1):1.
23. Fortin J, Boehm U, Weinstein MB, Graff JM, Bernard DJ. Follicle-stimulating
hormone synthesis and fertility are intact in mice lacking SMAD3 DNA binding
activity and SMAD2 in gonadotrope cells. FASEB J (2014) 28(3):1474–85. doi: 10.1096/
fj.13-237818
4. Plant TM. 60 YEARS OF NEUROENDOCRINOLOGY: The hypothalamopituitary-gonadal axis. J Endocrinol (2015) 226(2):T41–54.
5. Herbison AE. Control of puberty onset and fertility by gonadotropin-releasing
hormone neurons. Nat Rev Endocrinol (2016) 12(8):452–66.
24. Tran S, Zhou X, Lafleur C, Calderon MJ, Ellsworth BS, Kimmins S, et al.
Impaired fertility and FSH synthesis in gonadotrope-specific Foxl2 knockout mice. Mol
Endocrinol (2013) 27(3):407–21. doi: 10.1210/me.2012-1286
6. Walker WH, Cheng J. FSH and testosterone signaling in sertoli cells.
Reproduction (2005) 130(1):15–28.
7. Lunenfeld B. Gonadotropin stimulation: past, present and future. Reprod Med
Biol (2011) 11(1):11–25.
25. Li Y, Schang G, Boehm U, Deng CX, Graff J, Bernard DJ. SMAD3 regulates
follicle-stimulating hormone synthesis by pituitary gonadotrope cells in vivo. J Biol
Chem (2017) 292(6):2301–14. doi: 10.1074/jbc.M116.759167
8. Kallman FJ, Schoenfeld WA, Barrera SE. The genetic aspects of primary
hypogonadism. Am J Ment Defic (1944) 48:203–36.
9. Nowakowski H, Lenz W. Genetic aspects in male hypogonadism. Recent Prog
Horm Res (1961) 17):53–95.
26. Ulloa-Aguirre A, Reiter E, Crepieux P. FSH receptor signaling: Complexity of
interactions and signal diversity. Endocrinology (2018) 159(8):3020–35. doi: 10.1210/
en.2018-00452
10. Amoss M, Burgus R, Blackwell R, Vale W, Fellows R, Guillemin R. Purification,
amino acid composition and n-terminus of the hypothalamic luteinizing hormone
releasing factor (LRF) of ovine origin. Biochem Biophys Res Commun (1971) 44(1):205–
10. doi: 10.1016/S0006-291X(71)80179-1
27. Bhattacharya I, Pradhan BS, Sarda K, Gautam M, Basu S, Majumdar SS. A
switch in sertoli cell responsiveness to FSH may be responsible for robust onset of germ
cell differentiation during prepubartal testicular maturation in rats. Am J Physiol
Endocrinol Metab (2012) 303(7):E886–98. doi: 10.1152/ajpendo.00293.2012
11. Matsuo H, Baba Y, Nair RMG, Arimura A, Schally AV. Structure of the porcine
LH- and FSH-releasing hormone. i. the proposed amino acid sequence. Biochem
Biophys Res Commun (1971) 43(6):1334–9. doi: 10.1016/S0006-291X(71)80019-0
28. Bhattacharya I, Sharma SS, Sarkar H, Gupta A, Pradhan BS, Majumdar SS. FSH
mediated cAMP signalling upregulates the expression of ga subunits in pubertal rat
sertoli cells. Biochem Biophys Res Commun (2021) 569:100–5. doi: 10.1016/
j.bbrc.2021.06.094
12. Wade N. Guillemin and schally: a race spurred by rivalry. Science (1978) 200
(4341):510–3. doi: 10.1126/science.201.4355.510.a
29. Majumdar SS, Sarda K, Bhattacharya I, Plant TM. Insufficient androgen and
FSH signaling may be responsible for the azoospermia of the infantile primate testes
despite exposure to an adult-like hormonal milieu. Hum Reprod (2012) 27(8):2515–25.
doi: 10.1093/humrep/des184
13. Cattanach BM, Iddon CA, Charlton HM, Chiappa SA, Fink G. Gonadotrophinreleasing hormone deficiency in a mutant mouse with hypogonadism. Nature (1977)
269(5626):338–40. doi: 10.1038/269338a0
30. Bhattacharya I, Basu S, Sarda K, Gautam M, Nagarajan P, Pradhan BS, et al. Low
levels of gas and Ric8b in testicular sertoli cells may underlie restricted FSH action
during infancy in primates. Endocrinology (2015) 156(3):1143–55. doi: 10.1210/
en.2014-1746
14. McLachlan RI, O’Donnell L, Meachem SJ, Stanton PG, de Kretser DM, Pratis K,
et al. Identification of specific sites of hormonal regulation in spermatogenesis in rats,
monkeys, and man. Recent Prog Horm Res (2002) 57:149–79. doi: 10.1210/rp.57.1.149
15. Plant TM, Marshall GR. The functional significance of FSH in spermatogenesis
and the control of its secretion in Male primates. Endocr Rev (2001) 22(6):764–86. doi:
10.1210/edrv.22.6.0446
31. Chowdhury M, Steinberger E. Pituitary and plasma levels of gonadotrophins in
foetal and newborn male and female rats. J Endocrinol (1976) 69(3):381–4. doi:
10.1677/joe.0.0690381
16. Ruwanpura SM, McLachlan RI, Meachem SJ. Hormonal regulation of male
germ cell development. J Endocrinol (2010) 205(2):117–31. doi: 10.1677/JOE-10-0025
32. Ketelslegers JM, Hetzel WD, Sherins RJ, Catt KJ. Developmental changes in
testicular gonadotropin receptors: plasma gonadotropins and plasma testosterone in
the rat. Endocrinology (1978) 103(1):212–22. doi: 10.1210/endo-103-1-212
17. Ramaswamy S, Weinbauer GF. Endocrine control of spermatogenesis: Role of
FSH and LH/ testosterone. Spermatogenesis (2015) 4(2):e996025.
33. Clements JA, Reyes FI, Winter JSD, Faiman C. Studies on human sexual
development. III. fetal pituitary and serum, and amniotic fluid concentrations of LH,
CG, and FSH. J Clin Endocrinol Metab (1976) 42(1):9–19.
18. Kumar TR. Mouse models for the study of synthesis, secretion, and action of
pituitary gonadotropins. Prog Mol Biol Transl Sci (2016) 143:49–84. doi: 10.1016/
bs.pmbts.2016.08.006
19. Jonas KC, Oduwole OO, Peltoketo H, Rulli SB, Huhtaniemi IT. Mouse models of
altered gonadotrophin action: insight into male reproductive disorders. Reproduction
(2014) 148(4):R63–70. doi: 10.1530/REP-14-0302
34. Dunkel L, Alfthan H, Stenman UH, Selstam G, Rosberg S, Albertsson-Wikland
K. Developmental changes in 24-hour profiles of luteinizing hormone and folliclestimulating hormone from prepuberty to midstages of puberty in boys. J Clin
Endocrinol Metab (1992) 74(4):890–7. doi: 10.1210/jcem.74.4.1548356
20. de Gendt K, Verhoeven G. Tissue- and cell-specific functions of the androgen
receptor revealed through conditional knockout models in mice. Mol Cell Endocrinol
(2012) 352(1–2):13–25. doi: 10.1016/j.mce.2011.08.008
35. Huhtaniemi IT, Yamamoto M, Ranta T, Jalkanen J, Jaffe RB. Follicle-stimulating
hormone receptors appear earlier in the primate fetal testis than in the ovary. J Clin
Endocrinol Metab (1987) 65(6):1210–4. doi: 10.1210/jcem-65-6-1210
Frontiers in Endocrinology
10
frontiersin.org
Bhattacharya et al.
10.3389/fendo.2023.1110572
36. Lee BC, Pineda JL, Spiliotis BE, Brown TJ, Bercu BB. Male Sexual development
in the nonhuman primate. III. sertoli cell culture and age-related differences. Biol
Reprod (1983) 28(5):1207–15.
the FSH receptor leads to aberrant gametogenesis and hormonal imbalance. Proc Natl
Acad Sci U.S.A. (1998) 95(23):13612–7. doi: 10.1073/pnas.95.23.13612
58. Kumar TR, Wang Y, Lu N, Matzuk MM. Follicle stimulating hormone is
required for ovarian follicle maturation but not male fertility. Nat Genet (1997) 15
(2):201–4. doi: 10.1038/ng0297-201
37. Heckert LL, Griswold MD. The expression of the follicle-stimulating hormone
receptor in spermatogenesis. Recent Prog Horm Res (2002) 57:129–48. doi: 10.1210/
rp.57.1.129
59. Oduwole OO, Peltoketo H, Poliandri A, Vengadabady L, Chrusciel M, Doroszko M,
et al. Constitutively active follicle-stimulating hormone receptor enables androgenindependent spermatogenesis. J Clin Invest (2018) 128(5):1787–92. doi: 10.1172/JCI96794
38. Maguire SM, Tribley WA, Griswold MD. Follicle-stimulating hormone (FSH)
regulates the expression of FSH receptor messenger ribonucleic acid in cultured sertoli
cells and in hypophysectomized rat testis. Biol Reprod (1997) 56(5):1106–11. doi:
10.1095/biolreprod56.5.1106
60. Tapanainen JS, Aittomäki K, Min J, Vaskivuo T, Huhtaniemi IT. Men
homozygous for an inactivating mutation of the follicle-stimulating hormone (FSH)
receptor gene present variable suppression of spermatogenesis and fertility. Nat Genet
(1997) 15(2):205–6. doi: 10.1038/ng0297-205
39. Viswanathan P, Wood MA, Walker WH. Follicle-stimulating hormone (FSH)
transiently blocks FSH receptor transcription by increasing inhibitor of
deoxyribonucleic acid binding/differentiation-2 and decreasing upstream stimulatory
factor expression in rat sertoli cells. Endocrinology (2009) 150(8):3783–91. doi: 10.1210/
en.2008-1261
61. Bremner WJ, Matsumoto AM, Sussman AM, Paulsen C. Follicle-stimulating
hormone and human spermatogenesis. J Clin Invest (1981) 68(4):1044–52. doi: 10.1172/
JCI110327
40. Al-Attar L, Noël K, Dutertre M, Belville C, Forest MG, Burgoyne PS, et al.
Hormonal and cellular regulation of sertoli cell anti-müllerian hormone production in
the postnatal mouse. J Clin Invest (1997) 100(6):1335–43. doi: 10.1172/JCI119653
62. Foresta C, Bettella A, Ferlin A, Garolla A, Rossato M. Evidence for a stimulatory
role of follicle-stimulating hormone on the spermatogonial population in adult males.
Fertil Steril (1998) 69(4):636–42. doi: 10.1016/S0015-0282(98)00008-9
41. Grinspon RP, Urrutia M, Rey RA. Male Central hypogonadism in paediatrics the relevance of follicle-stimulating hormone and sertoli cell markers. Eur Endocrinol
(2018) 14(2):67–71. doi: 10.17925/EE.2018.14.2.67
63. Matsumoto AM, Karpas AE, Paulsen CA, Bremner WJ. Reinitiation of sperm
production in gonadotropin-suppressed normal men by administration of folliclestimulating hormone. J Clin Invest (1983) 72(3):1005–15. doi: 10.1172/JCI111024
42. Orth JM. The role of follicle-stimulating hormone in controlling sertoli cell
proliferation in testes of fetal rats. Endocrinology (1984) 115(4):1248–55. doi: 10.1210/
endo-115-4-1248
64. Matsumoto AM, Paulsen CA, Bremner WJ. Stimulation of sperm production by
human luteinizing hormone in gonadotropin-suppressed normal men. J Clin
Endocrinol Metab (1984) 59(5):882–7. doi: 10.1210/jcem-59-5-882
43. Orth JM, Gunsalus GL, Lamperti AA. Evidence from sertoli cell-depleted rats
indicates that spermatid number in adults depends on numbers of sertoli cells
produced during perinatal development. Endocrinology (1988) 122(3):787–94. doi:
10.1210/endo-122-3-787
65. van Alphen MMA, van de Kant HJG, de Rooij DG. Follicle-stimulating
hormone stimulates spermatogenesis in the adult monkey. Endocrinology (1988) 123
(3):1449–55. doi: 10.1210/endo-123-3-1449
66. Marshall GR, Zorub DS, Plant TM. Follicle-stimulating hormone amplifies the
population of differentiated spermatogonia in the hypophysectomized testosteronereplaced adult rhesus monkey (Macaca mulatta). Endocrinology (1995) 136(8):3504–11.
doi: 10.1210/endo.136.8.7628387
44. Johnston H, Baker PJ, Abel M, Charlton HM, Jackson G, Fleming L, et al.
Regulation of sertoli cell number and activity by follicle-stimulating hormone and
androgen during postnatal development in the mouse. Endocrinology (2004) 145
(1):318–29. doi: 10.1210/en.2003-1055
45. Allan CM, Garcia A, Spaliviero J, Zhang FP, Jimenez M, Huhtaniemi I, et al.
Complete sertoli cell proliferation induced by follicle-stimulating hormone (FSH)
independently of luteinizing hormone activity: evidence from genetic models of
isolated FSH action. Endocrinology (2004) 145(4):1587–93. doi: 10.1210/en.2003-1164
67. Weinbauer GF, Behre HM, Fingscheidt U, Nieschlag E. Human folliclestimulating hormone exerts a stimulatory effect on spermatogenesis, testicular size,
and serum inhibin levels in the gonadotropin-releasing hormone antagonist-treated
nonhuman primate (Macaca fascicularis). Endocrinology (1991) 129(4):1831–9. doi:
10.1210/endo-129-4-1831
46. Mc lachlan RI, Wreford NG, Kretser DMD, Robertson DM. The effects of
recombinant follicle-stimulating hormone on the restoration of spermatogenesis in the
gonadotropin-releasing hormone-immunized adult rat. Endocrinology (1995) 136
(9):4035–43. doi: 10.1210/endo.136.9.7649112
68. Simorangkir DR, Ramaswamy S, Marshall GR, Pohl CR, Plant TM. A selective
monotropic elevation of FSH, but not that of LH, amplifies the proliferation and
differentiation of spermatogonia in the adult rhesus monkey (Macaca mulatta). Hum
Reprod (2009) 24(7):1584–95. doi: 10.1093/humrep/dep052
47. Russell LD, Kershaw M, Borg KE, Shennawy A, Rulli SS, Gates RJ, et al.
Hormonal regulation of spermatogenesis in the hypophysectomized rat: FSH
maintenance of cellular viability during pubertal spermatogenesis. J Androl (1998) 19
(3):308–19.
69. Matthiesson KL, McLachlan RI, O’Donnell L, Frydenberg M, Robertson DM,
Stanton PG, et al. The relative roles of follicle-stimulating hormone and luteinizing
hormone in maintaining spermatogonial maturation and spermiation in normal men. J
Clin Endocrinol Metab (2006) 91(10):3962–9. doi: 10.1210/jc.2006-1145
48. Hikim APS, Swerdloff RS. Temporal and stage-specific effects of recombinant
human follicle-stimulating hormone on the maintenance of spermatogenesis in
gonadotropin-releasing hormone antagonist-treated rat. Endocrinology (1995) 136
(1):253–61. doi: 10.1210/endo.136.1.7828538
70. Matsumoto AM, Karpas AE, Bremner WJ. Chronic human chorionic
gonadotropin administration in normal men: evidence that follicle-stimulating
hormone is necessary for the maintenance of quantitatively normal spermatogenesis
in man. J Clin Endocrinol Metab (1986) 62(6):1184–92. doi: 10.1210/jcem-62-6-1184
49. Meachem SJ, Ruwanpura SM, Ziolkowski J, Ague JM, Skinner MK, Loveland
KL. Developmentally distinct in vivo effects of FSH on proliferation and apoptosis
during testis maturation. J Endocrinol (2005) 186(3):429–46. doi: 10.1677/joe.1.06121
71. Gromoll J, Simoni M, Nieschlag E. An activating mutation of the folliclestimulating hormone receptor autonomously sustains spermatogenesis in a
hypophysectomized man. J Clin Endocrinol Metab (1996) 81(4):1367–70.
50. Singh J, Handelsman DJ. Neonatal administration of FSH increases sertoli cell
numbers and spermatogenesis in gonadotropin-deficient (hpg) mice. J Endocrinol
(1996) 151(1):37–48. doi: 10.1677/joe.0.1510037
72. Phillip M, Arbelle JE, Segev Y, Parvari R. Male Hypogonadism due to a mutation
in the gene for the beta-subunit of follicle-stimulating hormone. N Engl J Med (1998)
338(24):1729–32. doi: 10.1056/NEJM199806113382404
51. Allan CM, Haywood M, Swaraj S, Spaliviero J, Koch A, Jimenez M, et al. A novel
transgenic model to characterize the specific effects of follicle-stimulating hormone on
gonadal physiology in the absence of luteinizing hormone actions. Endocrinology
(2001) 142(6):2213–20. doi: 10.1210/endo.142.6.8092
73. Simoni M, Casarini L. Mechanisms in endocrinology: Genetics of FSH action: a 2014and-beyond view. Eur J Endocrinol (2014) 170(3):R91–107. doi: 10.1530/EJE-13-0624
74. Zheng J, Mao J, Cui M, Liu Z, Wang X, Xiong S, et al. Novel FSHb mutation in a
male patient with isolated FSH deficiency and infertility. Eur J Med Genet (2017) 60
(6):335–9. doi: 10.1016/j.ejmg.2017.04.004
52. Haywood M, Tymchenko N, Spaliviero J, Koch A, Jimenez M, Gromoll J, et al.
An activated human follicle-stimulating hormone (FSH) receptor stimulates FSH-like
activity in gonadotropin-deficient transgenic mice. Mol Endocrinol (2002) 16
(11):2582–91. doi: 10.1210/me.2002-0032
75. Layman LC, Porto ALA, Xie J, da Motta LACR, da Motta LDC, Weiser W, et al.
FSH beta gene mutations in a female with partial breast development and a male sibling
with normal puberty and azoospermia. J Clin Endocrinol Metab (2002) 87(8):3702–7.
53. Allan CM, Lim P, Robson M, Spaliviero J, Handelsman DJ. Transgenic mutant
D567G but not wild-type human FSH receptor overexpression provides FSHindependent and promiscuous glycoprotein hormone sertoli cell signaling. Am J
Physiol Endocrinol Metab (2009) 296(5):E1022-28. doi: 10.1152/ajpendo.90941.2008
76. Rougier C, Hieronimus S, Panaïa-Ferrari P, Lahlou N, Paris F, Fenichel P.
Isolated follicle-stimulating hormone (FSH) deficiency in two infertile men without
FSH b gene mutation: Case report and literature review. Ann Endocrinol (Paris) (2019)
80(4):234–9. doi: 10.1016/j.ando.2019.06.002
54. Allan CM, Garcia A, Spaliviero J, Jimenez M. Maintenance of spermatogenesis
by the activated human (Asp567Gly) FSH receptor during testicular regression due to
hormonal withdrawal. Biol Reprod (2006) 74(5):938–44. doi: 10.1095/
biolreprod.105.048413
77. Mantovani G, Borgato S, Beck-Peccoz P, Romoli R, Borretta G, Persani L. Isolated
follicle-stimulating hormone (FSH) deficiency in a young man with normal virilization who
did not have mutations in the FSHb gene. Fertil Steril (2003) 79(2):434–6.
55. McDonald R, Sadler C, Kumar TR. Gain-of-Function genetic models to study
FSH action. Front Endocrinol (Lausanne) (2019) 10(FEB). doi: 10.3389/
fendo.2019.00028
78. Moudgal NR, Sairam MR, Krishnamurthy HN, Sridhar S, Krishnamurthy H, Khan
H. Immunization of male bonnet monkeys (M. radiata) with a recombinant FSH receptor
preparation affects testicular function and fertility. Endocrinology (1997) 138(7):3065–8.
56. Abel MH, Wootton AN, Wilkins V, Huhtaniemi I, Knight PG, Charlton HM.
The effect of a null mutation in the follicle-stimulating hormone receptor gene on
mouse reproduction. Endocrinology (2000) 141(5):1795–803. doi: 10.1210/
endo.141.5.7456
79. Moudgal NR, Murthy GS, Prasanna Kumar KM, Martin F, Suresh R,
Medhamurthy R, et al. Responsiveness of human male volunteers to immunization
with ovine follicle stimulating hormone vaccine: results of a pilot study. Hum Reprod
(1997) 12(3):457–63.
57. Dierich A, Sairam MR, Monaco L, Fimia GM, Gansmuller A, Lemeur M, et al.
Impairing follicle-stimulating hormone (FSH) signaling in vivo: targeted disruption of
80. Moudgal NR, Dighe RR. Is FSH based contraceptive vaccine a feasible
proposition for the human Male? Reprod Immunol (1999), 346–57.
Frontiers in Endocrinology
11
frontiersin.org
Bhattacharya et al.
10.3389/fendo.2023.1110572
105. Ramaswamy S, Walker WH, Aliberti P, Sethi R, Marshall GR, Smith A, et al.
The testicular transcriptome associated with spermatogonia differentiation initiated by
gonadotrophin stimulation in the juvenile rhesus monkey (Macaca mulatta). Hum
Reprod (2017) 32(10):2088–100. doi: 10.1093/humrep/dex270
81. Moudgal NR, Sairam MR. Is there a true requirement for follicle stimulating
hormone in promoting spermatogenesis and fertility in primates? Hum Reprod (1998)
13(4):916–9.
82. Nieschlag E, Simoni M, Gromoll J, Weinbauer GF. Role of FSH in the regulation
of spermatogenesis: clinical aspects. Clin Endocrinol (Oxf) (1999) 51(2):139–46. doi:
10.1046/j.1365-2265.1999.00846.x
106. Santulli R, Sprando RL, Awoniyi CA, Ewing LL, Zirkin BR, Zirkin BR. To what
extent can spermatogenesis be maintained in the hypophysectomized adult rat testis
with exogenously administered testosterone? Endocrinology (1990) 126(1):95–102. doi:
10.1210/endo-126-1-95
83. Teerds KJ, Huhtaniemi IT. Morphological and functional maturation of leydig
cells: from rodent models to primates. Hum Reprod Update (2015) 21(3):310–28. doi:
10.1093/humupd/dmv008
107. Awoniyi CA, Sprando RL, Santulli R, Chandrashekar V, Ewing LL, Zirkin BR,
et al. Restoration of spermatogenesis by exogenously administered testosterone in rats
made azoospermic by hypophysectomy or withdrawal of luteinizing hormone alone.
Endocrinology (1990) 127(1):177–84. doi: 10.1210/endo-127-1-177
84. Kumar DL, DeFalco T. A perivascular niche for multipotent progenitors in the
fetal testis. Nat Commun (2018) 9(1). doi: 10.1038/s41467-018-06996-3
85. Shima Y, Morohashi K-I. Leydig progenitor cells in fetal testis. Mol Cell
Endocrinol (2017) 445:55–64. doi: 10.1016/j.mce.2016.12.006
86. Inoue M, Baba T, Morohashi K-I. Recent progress in understanding the
mechanisms of leydig cell differentiation. Mol Cell Endocrinol (2018) 468:39–46. doi:
10.1016/j.mce.2017.12.013
108. Awoniyi CA, Santulli R, Chandrashekar V, Schanbacher BD, Zirkin BR.
Quantitative restoration of advanced spermatogenic cells in adult male rats made
azoospermic by active immunization against luteinizing hormone or gonadotropinreleasing hormone. Endocrinology (1989) 125(3):1303–9. doi: 10.1210/endo-125-31303
87. Huang X, Jia J, Sun M, Li M, Liu N. Mutational screening of the INSL 3 gene in
azoospermic males with a history of cryptorchidism. Andrologia (2016) 48(7):835–9.
doi: 10.1111/and.12522
109. Sun YT, Irby DC, Robertson DM, de Kretser DM. The effects of exogenously
administered testosterone on spermatogenesis in intact and hypophysectomized rats.
Endocrinology (1989) 125(2):1000–10. doi: 10.1210/endo-125-2-1000
88. Nowacka-Woszuk J, Krzeminska P, Nowak T, Gogulski M, Switonski M,
Stachowiak M. Analysis of transcript and methylation levels of INSL3 and RXFP2 in
undescended and descended dog testes suggested promising biomarkers associated
with cryptorchidism. Theriogenology (2020) 157:483–89. doi: 10.1016/
j.theriogenology.2020.08.029
110. Rea MA, Marshall GR, Weinbauer GF, Nieschlag E. Testosterone maintains
pituitary and serum FSH and spermatogenesis in gonadotrophin-releasing hormone
antagonist-suppressed rats. J Endocrinol (1986) 108(1):101–7. doi: 10.1677/
joe.0.1080101
111. Bartlett JMS, Weinbauer GF, Nieschlag E. Differential effects of FSH and
testosterone on the maintenance of spermatogenesis in the adult hypophysectomized
rat. J Endocrinol (1989) 121(1):49–58. doi: 10.1677/joe.0.1210049
89. Bhattacharya I, Sen Sharma S, Majumdar SS. Pubertal orchestration of
hormones and testis in primates. Mol Reprod Dev (2019) 86(11):1505–30. doi:
10.1002/mrd.23246
112. Whitcomb RW, Crowley WF. Clinical review 4: Diagnosis and treatment of
isolated gonadotropin-releasing hormone deficiency in men. J Clin Endocrinol Metab
(1990) 70(1):3–7. doi: 10.1210/jcem-70-1-3
90. Zirkin BR, Papadopoulos V. Leydig cells: formation, function, and regulation.
Biol Reprod (2018) 99(1):101–11. doi: 10.1093/biolre/ioy059
91. Zhang FP, Poutanen M, Wilbertz J, Huhtaniemi I. Normal prenatal but arrested
postnatal sexual development of luteinizing hormone receptor knockout (LuRKO)
mice. Mol Endocrinol (2001) 15(1):172–83. doi: 10.1210/mend.15.1.0582
113. Swerdloff RS, Bagatell CJ, Wang C, Anawalt BD, Berman N, Steiner B, et al.
Suppression of spermatogenesis in man induced by nal-glu gonadotropin releasing
hormone antagonist and testosterone enanthate (TE) is maintained by TE alone. J Clin
Endocrinol Metab (1998) 83(10):3527–33.
92. Ma X, Dong Y, Matzuk MM, Kumar TR. Targeted disruption of luteinizing
hormone beta-subunit leads to hypogonadism, defects in gonadal steroidogenesis, and
infertility. Proc Natl Acad Sci U.S.A. (2004) 101(49):17294–9. doi: 10.1073/
pnas.0404743101
114. Weinbauer GF, Limberger A, Behre HM, Nieschlag E. Can testosterone alone
maintain the gonadotrophin-releasing hormone antagonist-induced suppression of
spermatogenesis in the non-human primate? J Endocrinol (1994) 142(3):485–95. doi:
10.1677/joe.0.1420485
93. Yeh S, Tsai MY, Xu Q, Mu XM, Lardy H, Huang KE, et al. Generation and
characterization of androgen receptor knockout (ARKO) mice: an in vivo model for the
study of androgen functions in selective tissues. Proc Natl Acad Sci U.S.A. (2002) 99
(21):13498–503. doi: 10.1073/pnas.212474399
115. Marshall GR, Wickings EJ, Lüdecke DK, Nieschlag E. Stimulation of
spermatogenesis in stalk-sectioned rhesus monkeys by testosterone alone. J Clin
Endocrinol Metab (1983) 57(1):152–9. doi: 10.1210/jcem-57-1-152
94. O’Shaughnessy PJ, Johnston H, Willerton L, Baker PJ. Failure of normal adult
leydig cell development in androgen-receptor-deficient mice. J Cell Sci (2002) 115(Pt
17):3491–6. doi: 10.1242/jcs.115.17.3491
116. Marshall GR, Wickings EJ, Nieschlag E. Testosterone can initiate
spermatogenesis in an immature nonhuman primate, macaca fascicularis.
Endocrinology (1984) 114(6):2228–33. doi: 10.1210/endo-114-6-2228
95. Axelrod L, Neer RM, Kliman B. Hypogonadism in a male with immunologically
active, biologically inactive luteinizing hormone: an exception to a venerable rule. J Clin
Endocrinol Metab (1979) 48(2):279–87. doi: 10.1210/jcem-48-2-279
117. Marshall GR, Jockenhovel F, Ludecke D, Nieschlag E. Maintenance of complete
but quantitatively reduced spermatogenesis in hypophysectomized monkeys by
testosterone alone. Acta Endocrinol (Copenh) (1986) 113(3):424–31. doi: 10.1530/
acta.0.1130424
96. Weiss J, Axelrod L, Whitcomb RW, Harris PE, Crowley WF, Jameson JL.
Hypogonadism caused by a single amino acid substitution in the beta subunit of
luteinizing hormone. N Engl J Med (1992) 326(3):179–83. doi: 10.1056/
NEJM199201163260306
118. Weinbauer GF, Göckeler E, Nieschlag E. Testosterone prevents complete
suppression of spermatogenesis in the gonadotropin-releasing hormone antagonisttreated nonhuman primate (Macaca fascicularis). J Clin Endocrinol Metab (1988) 67
(2):284–90. doi: 10.1210/jcem-67-2-284
97. Valdes-Socin H, Salvi R, Daly AF, Gaillard RC, Quatresooz P, Tebeu PM, et al.
Hypogonadism in a patient with a mutation in the luteinizing hormone beta-subunit
gene. N Engl J Med (2004) 351(25):2619–25. doi: 10.1056/NEJMoa040326
119. Singh J, O’neill C, Handelsman DJ. Induction of spermatogenesis by androgens
in gonadotropin-deficient (hpg) mice. Endocrinology (1995) 136(12):5311–21. doi:
10.1210/endo.136.12.7588276
98. Lofrano-Porto A, Barra GB, Giacomini LA, Nascimento PP, Latronico AC,
Casulari LA, et al. Luteinizing hormone beta mutation and hypogonadism in men and
women. N Engl J Med (2007) 357(9):897–904. doi: 10.1056/NEJMoa071999
120. Singh J, Handelsman DJ. The effects of recombinant FSH on testosteroneinduced spermatogenesis in gonadotrophin-deficient (hpg) mice. J Androl (1996) 17
(4):382–93.
99. Basciani S, Watanabe M, Mariani S, Passeri M, Persichetti A, Fiore D, et al.
Hypogonadism in a patient with two novel mutations of the luteinizing hormone bsubunit gene expressed in a compound heterozygous form. J Clin Endocrinol Metab
(2012) 97(9):3031–8. doi: 10.1210/jc.2012-1986
121. Burris AS, Rodbard HW, Winters SJ, Sherins RJ. Gonadotropin therapy in men
with isolated hypogonadotropic hypogonadism: the response to human chorionic
gonadotropin is predicted by initial testicular size. J Clin Endocrinol Metab (1988) 66
(6):1144–51. doi: 10.1210/jcem-66-6-1144
100. Themmen APN, Huhtaniemi IT. Mutations of gonadotropins and
gonadotropin receptors: elucidating the physiology and pathophysiology of pituitarygonadal function. Endocr Rev (2000) 21(5):551–83. doi: 10.1210/edrv.21.5.0409
122. Fraietta R, Zylberstejn DS, Esteves SC. Hypogonadotropic hypogonadism
revisited. Clinics (Sao Paulo) (2013) 68 Suppl 1(Suppl 1):81–8. doi: 10.6061/clinics/
2013(Sup01)09
101. Grumbach MM. Commentary: A window of opportunity: The diagnosis of
gonadotropin deficiency in the male infant. J Clin Endocrinol Metab (2005) 90:3122–7.
doi: 10.1210/jc.2004-2465
123. Gromoll J, Eiholzer U, Nieschlag E, Simoni M. Male Hypogonadism caused by
homozygous deletion of exon 10 of the luteinizing hormone (LH) receptor: differential
action of human chorionic gonadotropin and LH. J Clin Endocrinol Metab (2000) 85
(6):2281–6. doi: 10.1210/jcem.85.6.6636
102. Marshall GR, Plant TM. Puberty occurring either spontaneously or induced
precociously in rhesus monkey (Macaca mulatta) is associated with a marked
proliferation of sertoli cells. Biol Reprod (1996) 54(6):1192–9. doi: 10.1095/
biolreprod54.6.1192
124. Martens JWM, Lumbroso S, Verhoef-Post M, Georget V, Richter-Unruh A,
Szarras-Czapnik M, et al. Mutant luteinizing hormone receptors in a compound
heterozygous patient with complete leydig cell hypoplasia: abnormal processing
causes signaling deficiency. J Clin Endocrinol Metab (2002) 87(6):2506–13. doi:
10.1210/jcem.87.6.8523
103. Majumdar SS, Winters SJ, Plant TM. A study of the relative roles of folliclestimulating hormone and luteinizing hormone in the regulation of testicular inhibin
secretion in the rhesus monkey (Macaca mulatta)*. Endocrinology (1997) 138:1363–73.
doi: 10.1210/endo.138.4.5058
125. Richter-Unruh A, Martens JWM, Verhoef-Post M, Wessels HT, Kors WA,
Sinnecker GHG, et al. Leydig cell hypoplasia: cases with new mutations, new
polymorphisms and cases without mutations in the luteinizing hormone receptor
gene. Clin Endocrinol (Oxf) (2002) 56(1):103–12. doi: 10.1046/j.03000664.2001.01437.x
104. Ramaswamy S, Plant TM, Marshall GR. Pulsatile stimulation with recombinant
single chain human luteinizing hormone elicits precocious sertoli cell proliferation in
the juvenile male rhesus monkey (Macaca mulatta). Biol Reprod (2000) 63(1):82–8. doi:
10.1095/biolreprod63.1.82
Frontiers in Endocrinology
12
frontiersin.org
Bhattacharya et al.
10.3389/fendo.2023.1110572
126. Richter-Unruh A, Korsch E, Hiort O, Holterhus PM, Themmen AP, Wudy SA.
Novel insertion frameshift mutation of the LH receptor gene: problematic clinical
distinction of leydig cell hypoplasia from enzyme defects primarily affecting
testosterone biosynthesis. Eur J Endocrinol (2005) 152(2):255–9. doi: 10.1530/
eje.1.01852
148. O’Grady MJ, McGrath N, Quinn FM, Capra ML, McDermott MB, Murphy NP.
Spermatogenesis in a prepubertal boy. J Pediatr (2012) 161(2):369.
149. McGee SR, Narayan P. Precocious puberty and leydig cell hyperplasia in male
mice with a gain of function mutation in the LH receptor gene. Endocrinology (2013)
154(10):3900–13. doi: 10.1210/en.2012-2179
127. Qiao J, Han B, Liu BL, Chen X, Ru Y, Cheng KX, et al. A splice site mutation
combined with a novel missense mutation of LHCGR cause male
pseudohermaphroditism. Hum Mutat (2009) 30(9):E855-65. doi: 10.1002/humu.21072
150. Bruysters M, Christin-Maitre S, Verhoef-Post M, Sultan C, Auger J, Faugeron I,
et al. A new LH receptor splice mutation responsible for male hypogonadism with
subnormal sperm production in the propositus, and infertility with regular cycles in an
affected sister. Hum Reprod (2008) 23(8):1917–23. doi: 10.1093/humrep/den180
128. Simoni M, Tüttelmann F, Michel C, Böckenfeld Y, Nieschlag E, Gromoll J.
Polymorphisms of the luteinizing hormone/chorionic gonadotropin receptor gene:
association with maldescended testes and male infertility. Pharmacogenet Genomics
(2008) 18(3):193–200. doi: 10.1097/FPC.0b013e3282f4e98c
151. Achard C, Courtillot C, Lahuna O, Mé duri G, Soufir JC, Lière P, et al. Normal
spermatogenesis in a man with mutant luteinizing hormone. N Engl J Med (2009) 361
(19):1856–63. doi: 10.1056/NEJMoa0805792
129. Richard N, Leprince C, Gruchy N, Pigny P, Andrieux J, Mittre H, et al.
Identification by array-comparative genomic hybridization (array-CGH) of a large
deletion of luteinizing hormone receptor gene combined with a missense mutation in a
patient diagnosed with a 46,XY disorder of sex development and application to prenatal
diagnosis. Endocr J (2011) 58(9):769–76. doi: 10.1507/endocrj.K11E-119
152. Morse HC, Horike N, Rowley MJ, Heller CG. Testosterone concentrations in
testes of normal men: effects of testosterone propionate administration. J Clin
Endocrinol Metab (1973) 37(6):882–6. doi: 10.1210/jcem-37-6-882
153. Zirkin BR, Santulli R, Awoniyi CA, Ewing LL. Maintenance of advanced
spermatogenic cells in the adult rat testis: quantitative relationship to testosterone
concentration within the testis. Endocrinology (1989) 124(6):3043–9. doi: 10.1210/
endo-124-6-3043
130. Kossack N, Troppmann B, Richter-Unruh A, Kleinau G, Gromoll J. Aberrant
transcription of the LHCGR gene caused by a mutation in exon 6A leads to leydig cell
hypoplasia type II. Mol Cell Endocrinol (2013) 366(1):59–67. doi: 10.1016/
j.mce.2012.11.018
154. Zhang FP, Pakarainen T, Poutanen M, Toppari J, Huhtaniemi I. The low
gonadotropin-independent constitutive production of testicular testosterone is
sufficient to maintain spermatogenesis. Proc Natl Acad Sci U.S.A. (2003) 100
(23):13692–7. doi: 10.1073/pnas.2232815100
131. Themmen APN. An update of the pathophysiology of human gonadotrophin
subunit and receptor gene mutations and polymorphisms. Reproduction (2005) 130
(3):263–74. doi: 10.1530/rep.1.00663
155. Walker WH. Androgen actions in the testis and the regulation of
spermatogenesis. Adv Exp Med Biol (2021) 1288:175–203. doi: 10.1007/978-3-03077779-1_9
132. Latronico A, Arnhold IP. Inactivating mutations of the human luteinizing
hormone receptor in both sexes. Semin Reprod Med (2012) 30(5):382–6. doi: 10.1055/s0032-1324721
156. Christin-Maitre S, Young J. Androgens and spermatogenesis. Ann Endocrinol
(Paris) (2022) 83(3):155–8. doi: 10.1016/j.ando.2022.04.010
133. Steinberger E, Root A, Ficher M, Smith KD. The role of androgens in the
initiation of spermatogenesis in man. J Clin Endocrinol Metab (1973) 37(5):746–51. doi:
10.1210/jcem-37-5-746
157. Rey R, Lukas-Croisier C, Lasala C, Bedecarrá s P. AMH/MIS: What we know
already about the gene, the protein and its regulation. Mol Cell Endocrinol (2003) 211
(1–2):21–31.
134. Shenker A, Laue L, Kosugi S, Merendino JJ, Minegishi T, Cutler GB. A
constitutively activating mutation of the luteinizing hormone receptor in familial
male precocious puberty. Nature (1993) 365(6447):652–4. doi: 10.1038/365652a0
158. McCabe MJ, Allan CM, Foo CFH, Nicholls PK, McTavish KJ, Stanton PG.
Androgen initiates sertoli cell tight junction formation in the hypogonadal (hpg)
mouse. Biol Reprod (2012) 87(2).
135. Latronico AC, Shinozaki H, Guerra GJr., Pereira MAA, Lemos Marini SH,
Baptista MTM, et al. Gonadotropin-independent precocious puberty due to luteinizing
hormone receptor mutations in Brazilian boys: a novel constitutively activating
mutation in the first transmembrane helix. J Clin Endocrinol Metab (2000) 85
(12):4799–805.
159. Cooke PS, Walker WH. Male Fertility in mice requires classical and
nonclassical androgen signaling. Cell Rep (2021) 36(7).
160. Dalmazzo A, Losano JDA, Angrimani DSR, Pereira IVA, Goissis MD,
Francischini MCP, et al. Immunolocalisation and expression of oxytocin receptors
and sex hormone-binding globulin in the testis and epididymis of dogs: Correlation
with sperm function. Reprod Fertil Dev (2019) 31(9):1434–43.
136. Soriano-Guillén L, Lahlou N, Chauvet G, Roger M, Chaussain JL, Carel JC. Adult
height after ketoconazole treatment in patients with familial male-limited precocious puberty.
J Clin Endocrinol Metab (2005) 90(1):147–51. doi: 10.1210/jc.2004-1438
161. Vos MJ, Mijnhout GS, Rondeel JMM, Baron W, Groeneveld PHP. Sex
hormone binding globulin deficiency due to a homozygous missense mutation. J
Clin Endocrinol Metab (2014) 99(9):E1798-802.
137. Soriano-Guillen L, Mitchell V, Carel JC, Barbet P, Roger M, Lahlou N.
Activating mutations in the luteinizing hormone receptor gene: a human model of
non-follicle-stimulating hormone-dependent inhibin production and germ cell
maturation. J Clin Endocrinol Metab (2006) 91(8):3041–7. doi: 10.1210/jc.2005-2564
162. Chang C, Chen YT, der YS, Xu Q, RS W, Guillou F, et al. Infertility with
defective spermatogenesis and hypotestosteronemia in male mice lacking the androgen
receptor in sertoli cells. Proc Natl Acad Sci U.S.A. (2004) 101(18):6876–81. doi: 10.1073/
pnas.0307306101
138. Nagasaki K, Katsumata N, Ogawa Y, Kikuchi T, Uchiyama M. Novel C617Y
mutation in the 7th transmembrane segment of luteinizing hormone/
choriogonadotropin receptor in a Japanese boy with peripheral precocious puberty.
Endocr J (2010) 57(12):1055–60. doi: 10.1507/endocrj.K10E-227
139. Liu G, Duranteau L, Carel JC, Monroe J, Doyle DA, Shenker A. Leydig-cell
tumors caused by an activating mutation of the gene encoding the luteinizing hormone
receptor. N Engl J Med (1999) 341(23):1731–6. doi: 10.1056/NEJM199912023412304
163. de Gendt K, Swinnen JV, Saunders PTK, Schoonjans L, Dewerchin M, Devos
A, et al. A sertoli cell-selective knockout of the androgen receptor causes spermatogenic
arrest in meiosis. Proc Natl Acad Sci U.S.A. (2004) 101(5):1327–32. doi: 10.1073/
pnas.0308114100
140. Zarrilli S, Lombardi G, Pacsano L, di Somma C, Colao A, Mirone V, et al.
Hormonal and seminal evaluation of leydig cell tumour patients before and after
orchiectomy. Andrologia (2000) 32(3):147–54. doi: 10.1046/j.1439-0272.2000.00356.x
164. Holdcraft RW, Braun RE. Androgen receptor function is required in sertoli
cells for the terminal differentiation of haploid spermatids. Development (2004) 131
(2):459–67. doi: 10.1242/dev.00957
141. Richter-Unruh A, Wessels HT, Menken U, Bergmann M, Schmittmann-Ohters
K, Schaper J, et al. Male LH-independent sexual precocity in a 3.5-year-old boy caused
by a somatic activating mutation of the LH receptor in a leydig cell tumor. J Clin
Endocrinol Metab (2002) 87(3):1052–6.
165. O’Hara L, McInnes K, Simitsidellis I, Morgan S, Atanassova N, SlowikowskaHilczer J, et al. Autocrine androgen action is essential for leydig cell maturation and
function, and protects against late-onset leydig cell apoptosis in both mice and men.
FASEB J (2015) 29(3):894–910. doi: 10.1096/fj.14-255729
142. Canto P, Söderlund D, Ramó n G, Nishimura E, Mé ndez JP. Mutational
analysis of the luteinizing hormone receptor gene in two individuals with leydig cell
tumors. Am J Med Genet (2002) 108(2):148–52. doi: 10.1002/ajmg.10218
166. Xu Q, Lin HY, Yeh Sd, Yu IC, Wang RS, Chen YT, et al. Infertility with
defective spermatogenesis and steroidogenesis in male mice lacking androgen receptor
in leydig cells. Endocrine (2007) 32(1):96–106. doi: 10.1007/s12020-007-9015-0
143. Sangkhathat S, Kanngurn S, Jaruratanasirikul S, Tubtawee T, Chaiyapan W,
Patrapinyokul S, et al. Peripheral precocious puberty in a Male caused by leydig cell
adenoma harboring a somatic mutation of the LHR gene: Report of a case. J Med Assoc
Thai (2010) 93(9):1093.
167. Zhang C, Yeh S, Chen YT, Wu CC, Chuang KH, Lin HY, et al.
Oligozoospermia with normal fertility in male mice lacking the androgen receptor in
testis peritubular myoid cells. Proc Natl Acad Sci U.S.A. (2006) 103(47):17718–23. doi:
10.1073/pnas.0608556103
144. Boot AM, Lumbroso S, Verhoef-Post M, Richter-Unruh A, Looijenga LHJ, Funaro
A, et al. Mutation analysis of the LH receptor gene in leydig cell adenoma and hyperplasia
and functional and biochemical studies of activating mutations of the LH receptor gene. J
Clin Endocrinol Metab (2011) 96(7): E1197-205. doi: 10.1210/jc.2010-3031
168. Welsh M, Saunders PTK, Atanassova N, Sharpe RM, Smith LB. Androgen
action via testicular peritubular myoid cells is essential for male fertility. FASEB J (2009)
23(12):4218–30. doi: 10.1096/fj.09-138347
145. Shenker A. Activating mutations of the lutropin choriogonadotropin receptor
in precocious puberty. Recept Channels (2002) 8(1):3–18. doi: 10.3109/
10606820212138
169. Tsai MY, Yeh Sd, Wang RS, Yeh S, Zhang C, Lin HY, et al. Differential effects of
spermatogenesis and fertility in mice lacking androgen receptor in individual testis
cells. Proc Natl Acad Sci U.S.A. (2006) 103(50):18975–80. doi: 10.1073/
pnas.0608565103
146. Polepalle SK, Shabaik A, Alagiri M. Leydig cell tumor in a child with
spermatocyte maturation and no pseudoprecocious puberty. Urology (2003) 62
(3):551. doi: 10.1016/S0090-4295(03)00469-2
170. Lyon MF, Glenister PH, Lynn Lamoreux M. Normal spermatozoa from
androgen-resistant germ cells of chimaeric mice and the role of androgen in
spermatogenesis. Nature (1975) 258(5536):620–2. doi: 10.1038/258620a0
147. Cajaiba MM, Reyes-Mú gica M, Rios JCS, Nistal M. Non-tumoural parenchyma
in leydig cell tumours: pathogenetic considerations. Int J Androl (2008) 31(3):331–6.
doi: 10.1111/j.1365-2605.2007.00774.x
171. O’Shaughnessy PJ, Verhoeven G, de Gendt K, Monteiro A, Abel MH. Direct
action through the sertoli cells is essential for androgen stimulation of spermatogenesis.
Endocrinology (2010) 151(5):2343–8. doi: 10.1210/en.2009-1333
Frontiers in Endocrinology
13
frontiersin.org
Bhattacharya et al.
10.3389/fendo.2023.1110572
172. Arslan M, Weinbauer GF, Schlatt S, Shahab M, Nieschlag E. FSH and
testosterone, alone or in combination, initiate testicular growth and increase the
number of spermatogonia and sertoli cells in a juvenile non-human primate
(Macaca mulatta). J Endocrinol (1993) 136(2):235–43. doi: 10.1677/joe.0.1360235
follicle-stimulating hormone alone or in combination with testosterone. Endocrinology
(2003) 144(2):509–17. doi: 10.1210/en.2002-220710
180. Abel MH, Baker PJ, Charlton HM, Monteiro A, Verhoeven G, de Gendt K,
et al. Spermatogenesis and sertoli cell activity in mice lacking sertoli cell receptors for
follicle-stimulating hormone and androgen. Endocrinology (2008) 149(7):3279–85. doi:
10.1210/en.2008-0086
173. Schlatt S, Arslan M, Weinbauer GF, Behre HM, Nieschlag E. Endocrine control
of testicular somatic and premeiotic germ cell development in the immature testis of
the primate macaca mulatta. Eur J Endocrinol (1995) 133(2):235–47. doi: 10.1530/
eje.0.1330235
181. O’Shaughnessy PJ, Monteiro A, Abel M. Testicular development in mice
lacking receptors for follicle stimulating hormone and androgen. PloS One (2012) 7
(4). doi: 10.1371/journal.pone.0035136
174. Acosta AA, Khalifa E, Oehninger S. Pure human follicle stimulating hormone has a
role in the treatment of severe male infertility by assisted reproduction: Norfolk’s total
experience. Hum Reprod (1992) 7(8):1067–72. doi: 10.1093/oxfordjournals.humrep.a137794
182. Grinspon RP, Bergadá I, Rey RA. Male Hypogonadism and disorders of sex
development. Front Endocrinol (Lausanne) (2020) 11.
175. Burgué s S, Calderó n MD. Subcutaneous self-administration of highly purified
follicle stimulating hormone and human chorionic gonadotrophin for the treatment of
male hypogonadotrophic hypogonadism. Spanish collaborative group on Male
hypogonadotropic hypogonadism. Hum Reprod (1997) 12(5):980–6.
183. Young J, Xu C, Papadakis GE, Acierno JS, Maione L, Hietamäki J, et al. Clinical
management of congenital hypogonadotropic hypogonadism. Endocr Rev (2019) 40
(2):669–710.
184. Soffientini U, Rebourcet D, Abel MH, Lee S, Hamilton G, Fowler PA, et al.
Identification of sertoli cell-specific transcripts in the mouse testis and the role of FSH
and androgen in the control of sertoli cell activity. BMC Genomics (2017) 18(1).
176. Kliesch S, Behre HM, Nieschlag E. Recombinant human follicle-stimulating hormone
and human chorionic gonadotropin for induction of spermatogenesis in a hypogonadotropic
male. Fertil Steril (1995) 63(6):1326–8. doi: 10.1016/S0015-0282(16)57619-5
185. Majumdar SS, Bhattacharya I. Genomic and post-genomic leads toward
regulation of spermatogenesis. Prog Biophys Mol Biol (2013) 113(3):409–22.
177. Kung AWC, Zhong YY, Lam KSL, Wang C. Induction of spermatogenesis with
gonadotrophins in Chinese men with hypogonadotrophic hypogonadism. Int J Androl
(1994) 17(5):241–7. doi: 10.1111/j.1365-2605.1994.tb01249.x
186. Suzuki S, Diaz VD, Hermann BP. What has single-cell RNA-seq taught us
about mammalian spermatogenesis? Biol Reprod (2019) 101(3):617–34.
178. Bhattacharya I, Basu S, Pradhan BS, Sarkar H, Nagarajan P, Majumdar SS.
Testosterone augments FSH signaling by upregulating the expression and activity of
FSH-receptor in pubertal primate sertoli cells. Mol Cell Endocrinol (2019) 482:70–80.
doi: 10.1016/j.mce.2018.12.012
187. Shen Y-C, Shami AN, Moritz L, Larose H, Manske GL, Ma Q, et al. TCF21+
mesenchymal cells contribute to testis somatic cell development, homeostasis, and
regeneration in mice. Nat Commun (2021) 12(1).
188. Rabbani M, Zheng X, Manske GL, Vargo A, Shami AN, Li JZ, et al. Decoding
the spermatogenesis program: New insights from transcriptomic analyses. Annu Rev
Genet (2022) 56(1):339–68.
179. Haywood M, Spaliviero J, Jimemez M, King NJC, Handelsman DJ, Allan CM.
Sertoli and germ cell development in hypogonadal (hpg) mice expressing transgenic
Frontiers in Endocrinology
14
frontiersin.org