The physiology of corticotropin-releasing factor (CRF).

Corticotropin-releasing factor (CRF) was characterized, purified and synthesized in 1981 by Vale. The composition of this 41 amino-acid peptide varies slightly from one species to another. Its principal origin is the paraventricular nucleus of the hypothalamus and, by the portal vessels, it reaches the adenohypophysis where it stimulates the corticotrophs. The effects of CRF have been analysed by in vitro and in vivo experiments. Some actions on the autonomic nervous system have been described. The action of CRF on adrenocorticotrophic hormone (ACTH) secretion is predominant, but it acts in relation with arginine-vasopressin and accessorily with angiotensin and catecholamines. Adrenal steroids act on feedback control of CRF secretion in the hypothalamus and also on pituitary corticotrophs. The CRF function starts between the 16th and 19th day in the fetal rat. The placenta is able to produce CRF.