Growth Hormone-Releasing Hormone
Growth hormone-releasing hormone is a peptide hormone secreted by the hypothalamus. Upon binding to GHRH receptors on somatotrophs in the pituitary gland, GHRH regulates the synthesis and release of growth hormone (GH) in the anterior pituitary gland. GH acts directly on GH receptors in various peripheral tissues, whereas in the liver it stimulates the production of insulin-like growth factor 1(IGF-1), a potent mitogen for various cell types including tumors. GHRH is a crucial neuroendocrine component of the neuroendocrine axis constituted by hypothalamic GHRH-pituitary GH and hepatic IGF-1 and is essential for its function. GHRH can also act as an autocrine and paracrine growth factor in human cancers.
The existence of growth hormone-releasing hormone (GHRH) was first suggested in 1961 and the identification of the structure of this 44-amino-acid peptide was made in 1981 from...