Thyrotropin-releasing hormone (TRH; MIM 275120), a small
neuropeptide, is widely distributed throughout the central and
peripheral nervous system as well as in extraneural tissues. The
peptide is synthesized in the hypothalamus and transported by the
portal vascular system to the anterior pituitary where it acts on
thyrotropic and lactotropic cells to promote secretion of TSH and
prolactin, respectively. Thyrotropin-releasing hormone receptor is
a G protein-coupled receptor that activates the inositol
phospholipid-calcium-protein kinase C transduction pathway upon the
binding of TRH. The TRHR gene is expressed in the thyrotrope cells
of the anterior pituitary.
