Corticotropin-releasing factor (CRF) is a 41-amino acid peptide derived from a 196-amino acid preprohormone. CRH belongs to corticotropin-releasing factor family and is secreted by the paraventricular nucleus (PVN) of the hypothalamus in response to stress. Ovine CRF produces a longer lasting ACTH response in humans than human CRF, mainly due to its longer plasma half-life.