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Growth Hormone Secretagogue Actions On The Pituitary Gland: Multiple Receptors For Multiple Ligands?
Author(s) -
Chen Chen
Publication year - 2000
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1046/j.1440-1681.2000.03258.x
Subject(s) - medicine , secretagogue , endocrinology , thyrotropin releasing hormone receptor , somatostatin , somatotropic cell , receptor , growth hormone releasing hormone receptor , growth hormone secretagogue receptor , chemistry , biology , growth hormone–releasing hormone , g protein coupled receptor , pituitary gland , hormone receptor , hormone , ghrelin , growth hormone , cancer , breast cancer
SUMMARY 1. Growth hormone (GH) secretion is thought to occur under the reciprocal regulation of two hypothalamic hormones, namely GH‐releasing hormone (GHRH) and somatostatin (SRIF), through their engagement with specific cell‐surface receptors on the anterior pituitary somatotropes. 2. In addition to GHRH and SRIF, synthetic GH‐releasing peptides (GHRP) or GH secretagogue(s) (GHS) regulate GH release through the activation of a novel receptor, the GHS receptor (GHS‐R). 3. The cloning of the GHS‐R from human, swine and rat identifies a novel G‐protein‐coupled receptor involved in the control of GH secretion and supports the existence of an undiscovered hormone that may activate this receptor. 4. Varieties of intracellular signalling systems are suggested to mediate the action of GHS, which include changes in intracellular free Ca 2+ ([Ca 2+ ] i ), cAMP, protein kinases A and C, phospholipase C etc. 5. With regard to the use of signalling systems by GHS, especially a new form of GHRP or GHRP‐2, a clear species difference has been demonstrated, supporting the possibility of more than one type of GHS‐R.