(CRH) 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 loop 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.... corticotrophin-releasing hormone