TRH Human

TRH is a tripeptide, consisting of three amino acids: pyroglutamyl-histidyl-proline amide . It is synthesized within parvocellular neurons of the paraventricular nucleus of the hypothalamus. The precursor polypeptide for TRH contains multiple copies of the sequence -Gln-His-Pro-Gly-, which undergoes several enzymatic processes to produce the mature TRH molecule .

TRH is transported to the anterior pituitary via the hypophyseal portal system, where it binds to TRH receptors on thyrotropes, stimulating the release of TSH. TSH then acts on the thyroid gland to promote the synthesis and release of thyroid hormones, which are essential for regulating metabolism, energy homeostasis, and various physiological functions .

Additionally, TRH can stimulate the release of prolactin from lactotropes in the anterior pituitary. Prolactin has various roles, including lactation in females and regulation of the immune system .

TRH has been used clinically for the treatment of conditions such as spinocerebellar degeneration and disturbances of consciousness . It also plays a role in diagnosing thyroid disorders through the TRH stimulation test, which assesses the pituitary gland’s response to TRH .

The structure of TRH was first determined and synthesized by Roger Guillemin and Andrew V. Schally in 1969. Both researchers made significant contributions to the understanding of TRH, although there was some debate over who identified the sequence first .

TRH affects various physiological functions, including energy homeostasis, feeding behavior, thermogenesis, metabolic rate, neuromuscular function, heart rate, and autonomic regulation . It may also act as a neurotransmitter in the nervous system, influencing arousal and feeding centers in the brain .