PLACENTAL CORTICOTROPIN-RELEASING HORMONE FUNCTION DURING HUMAN-PREGNANCY

Corticotropin releasing hormone (CRH) is produced in intrauterine site s including the placenta, decidua, and myometrium during human pregnan cy. Placental CRH may have endocrine, paracrine, and autocrine functio ns. Its output into the maternal circulation increases as a function o f gestation and correlates with increases in levels of mRNA encoding C RH in placental syncytiotrophoblast. Regulation of placental CRH expre ssion and activity is multifactorial, being inhibited by progesterone and nitric oxide (NO), and stimulated by cytokines, neuropeptides, and glucocorticoids. CRH acts as a vasodilator in perfused placental tiss ue in vitro, may modulate maternal and fetal pituitary function, and h as been implicated in mechanisms associated with the onset of labor at term and preterm.