Urocortin,a novel peptide of the corticotropin releasing hormone family

Urocortin, a novel peptide of the cortiotropin releasiong hormone (CRH) family, was discovered in 1995 in the rat brain and subsequently cloned and localized to human chromosome 2. It can bind to both CRH type 1 receptor and CRH type 2 receptor, as well as CRH binding protein. Especially to CRH type 2 receptor, urocortin binds to it with 40 times more potency than CRH does. Therefore, urocortin is thought to be an en dogenous ligand for CRH type 2 receptor. Immunoreactive urocortin and urocortin mRNA were localized in many areas such as mammalian brain, cardiovascular system, placenta. It is believed that urocortinmay play important physiological roles as a neuropeptide not only in the central nervous system but also in peripheral tissues.