Clinical Application of Thyrotropin-Releasing Hormone

Abstract

THYROTROPIN-releasing hormone (TRH) was the first of the hypothalamic regulatory factors to be purified. In 1969 its structure was shown to be the tripeptide, pyroglutamyl-histidyl-prolinamide,1 , 2 and it was synthesized by several groups.3 , 4 This molecule has been identified by immunoassay in the hypothalamus of many species. Its principal action in mammals is the release of thyroid-stimulating hormone (thyrotropin or TSH) from specific cells, the thyrotropes of the anterior pituitary gland. Synthesis of TRH occurs in several nuclei of the hypothalamus. TRH is secreted into the portal venous system traversing from hypothalamus directly to the pituitary gland. It interacts with specific receptors . . .