a peptide hypothalamic hormone (of 41 amino acids) stimulating the release of ACTH (adrenocorticotrophic hormone) from the anterior pituitary. Its own release is suppressed by a negative feedback loops involving cortisol, and its action is increased by antidiuretic hormone (see vasopressin) and angiotensin II. It can be administered intravenously as part of the CRH test, during which blood is analysed at 15-minute intervals for one hour for the ACTH response, which is excessive in cases of primary adrenal failure and suppressed in cases of anterior hypopituitarism.
Medical dictionary. 2011.