CRF (Corticotropin-releasing factor) is a family of related neuropeptides in vertebrates. This family includes corticotropin-releasing hormone, urotensin-I, urocortin, and sauvagine. The family can be grouped into 2 separate paralogous lineages, with urotensin-I, urocortin and sauvagine in one group and CRH forming the other group. Urocortin and sauvagine appear to represent orthologues of fish urotensin-I in mammals and amphibians, respectively. The peptides have a variety of physiological effects on stress and anxiety, vasoregulation, thermoregulation, growth and metabolism, metamorphosis and reproduction in various species, and are all released as prohormones.
Corticotropin-releasing hormone (CRH) is a releasing hormone found mainly in the paraventricular nucleus of the mammalian hypothalamus that regulates the release of corticotropin (ACTH) from the pituitary gland. The paraventricular nucleus transports CRH to the anterior pituitary, stimulating adrenocorticotropic hormone (ACTH) release via CRH type 1 receptors, thereby activating the hypothalamic-pituitary-adrenal axis (HPA) and, thus, glucocorticoid release.