Thyrotropin-releasing hormone (TRH)

Thyrotropin-releasing hormone (TRH) is a tripeptide hormone (pyroglutamyl-histidyl-proline amide) synthesized predominantly in the hypothalamus as a precursor protein (pro-TRH) and is cleaved to generate the mature form[2]. TRH stimulates the anterior pituitary to release thyroid-stimulating hormone (TSH) via binding to the TRH receptor, a G protein-coupled receptor (TRHR), as part of the hypothalamic-pituitary-thyroid axis, and also directly stimulates prolactin release from lactotropes[1][2][4]. Beyond its endocrine role, TRH acts as a neuromodulator in the central nervous system and is present in several tissues and brain regions, suggesting additional functions in autonomic regulation, mood, and other CNS pathways[2]. While clinically used synthetic analogs (e.g., protirelin, taltirelin) target the TRH receptor, TRH itself is a physiologic ligand and not itself a pharmacologic target. Dysregulation of TRH production or action contributes to hypothalamic-pituitary-thyroid dysregulation and is implicated in a range of neuroendocrine and possibly neuropsychiatric disorders[1][4].

Other names

Pro-thyrotropin-releasing hormonePro-TRHTRFProthyroliberinProtirelinTSH-releasing factorThyroliberinThyrotropin-releasing factor

TRH and its analogs act as agonists at the TRH receptor (TRHR), a G protein-coupled receptor, stimulating Gq-coupled signaling cascades and hormone release[1][4].