In The Blood Substance Is Too Low, It Stimulates Neuron Directly Stimulates The Gland
In The Blood Substance Is Too Low, It Stimulates Neuron Directly Stimulates The Gland
In The Blood Substance Is Too Low, It Stimulates Neuron Directly Stimulates The Gland
HORMONE
SECRETION
Humoral Trigger
2
Figure 25.2a-c
Humoral Trigger
Neuronal Trigger
Examples are oxytocin, ADH
(neurohypophysis hormones) and
Epinephrine (adrenal medulla
hormone)
Hormonal Trigger
This is when one endocrine gland releases
a hormone that stimulates another
endocrine gland to release its hormone.
Examples are any of the hypothalamus or
anterior pituitary hormones, and also the
adrenal cortex (steroid) hormones (except
aldosterone) and thyroid hormone.
The hypothalamus releases a hormone
that causes the pituitary gland to release
TSH, which causes the thyroid gland to
release thyroid hormone
Enzyme-linked receptors
Enzyme-linked receptors when
activated, function directly as
enzymes or are closely
associated with enzymes that
they activate.
When the hormone binds to
the extracellular part of the
receptor, an enzyme
immediately inside the cell
membrane is activated
One example of an enzymelinked receptor is the leptin
receptor.
Leptin is a hormone secreted
by fat cells it is especially
Measurement of
Hormone
Concentrations in the
Radioimmunoassay
Enzyme-Linked Immunosorbent
Assay
Blood
Radioimmunoassay (RIA) is a very sensitive in vitro assay
technique used to measure concentrations of antigens (for
example, hormone levels in blood) by use of antibodies which
are labeled with a radioactive substance.
ELISA (enzyme-linked immunosorbent assay) is a platebased assay technique designed for detecting and quantifying
substances such as peptides, proteins, antibodies and
hormones.