Releasing hormone 2143595 175478908 2007-12-03T13:31:20Z SmackBot 433328 Standard headings &/or gen fixes. using [[Project:AutoWikiBrowser|AWB]] A '''releasing hormone''' or '''releasing factor''' is a hormone whose main purpose is to control the release of another hormone. The main releasing hormones secreted by the hypothalamus are: *[[Thyrotropin-releasing hormone]] (TRH), *[[Corticotropin-releasing hormone]] (CRH), *[[Gonadotropin-releasing hormone]] (GnRH), *[[Growth hormone-releasing hormone]] (GHRH), Two other factors are also classed as releasing hormones, although they in fact inhibit pituitary hormone release *[[Somatostatin]], *[[Dopamine]]. For example, TRH is released from the [[hypothalamus]] in response to low levels of secretion of [[thyroid stimulating hormone]](TSH) from the [[pituitary gland]]. The TSH in turn is under feedback control by the [[thyroid]] hormones [[Thyroxine|T4]] and [[Triiodothyronine|T3]]. When the levels of TSH are too high, they feed back on the brain to shut down the secretion of TRH. Synthetic TRH is also used by physicians as a test of TSH reserve in the pituitary gland as it should stimulate the release of [[TSH]] and [[prolactin]] from this gland. [[Roger Guillemin]] and [[Andrew W. Schally]] were awarded the Nobel Prize in Physiology and Medicine in 1977 for their contributions to understanding "the peptide hormone production of the brain"; these scientists independently first isolated TRH and GnRH and then identified their structures. ==References== * Guillemin R. ''Hypothalamic hormones a.k.a. hypothalamic releasing factors.'' J Endocrinol 2005;184:11-28. [http://joe.endocrinology-journals.org/cgi/content/full/184/1/11 Fulltext]. PMID 15642779. ==See also== *[[Hormone]] *[[Neuroendocrinology]] [[Category:Hormones]] [[Category:Neuroendocrinology]]