The role of corticotropin-releasing hormone receptors in placenta and fetal membranes during human pregnancy.

Corticotropin-releasing hormone (CRH) is a 41 amino acid polypeptide that exerts a wide spectrum of hypothalamic and extrahypothalamic functions. Moreover, the placenta and other intrauterine tissues produce and secrete immunoreactive CRH. It has been demonstrated that placental CRH is secreted into the maternal circulation in large amounts during the third trimester of human pregnancy and may play an important role in the onset of labor. CRH exerts a number of functions within the intratuterine environment like induction of prostaglandin production and maintenance of the placental blood flow. Here we present an overview of current knowledge about the CRH receptor subtypes and their signaling properties within the feto-placental unit.