title: Corticotropin-releasing hormone-induced vasodilatation in the human fetal placental circulation.
abstract: The vasoactive effects of corticotropin-releasing hormone (CRH) in the human fetal-placental circulation in vitro have been investigated. Single lobules of term placentae were bilaterally perfused with constant flows of Krebs' solution (maternal and fetal, 5 ml/min, 95% O2, 5% CO2, 37 degrees C, pH 7.3) and changes in fetal-placental arterial perfusion pressure measured. Effects of human (hCRH) and ovine (oCRH) CRH were examined during submaximal vasoconstriction (100-120 mmHg) of the fetal-placental vasculature induced by prostaglandin F2 alpha (PGF2 alpha), (0.7-2 mumol/L). During infusion of hCRH or oCRH (24-7000 pmol/L) a concentration-dependent vasodilatation was observed. Human CRH and oCRH were equipotent as vasodilator agents (regression analysis; P > 0.05; n = 5). The vasodilator response curves to human and ovine CRH were compared to prostacyclin (PGI2) (1.2-1180 nmol/L). Human and oCRH were 53 times more potent than PGI2 (regression analysis, P < 0.05; n = 5). These results indicate that CRH has powerful vasodilator properties in the human fetal-placental circulation and may play a role in control of placental vascular resistance to blood flow.
authors.affiliation: Maternal Health Research Centre, John Hunter Hospital, Newcastle, NSW, Australia.
authors.forename: V L
authors.initials: VL
authors.lastname: Clifton
authors.forename: M A
authors.initials: MA
authors.lastname: Read
authors.forename: I M
authors.initials: IM
authors.lastname: Leitch
authors.forename: A L
authors.initials: AL
authors.lastname: Boura
authors.forename: P J
authors.initials: PJ
authors.lastname: Robinson
authors.forename: R
authors.initials: R
authors.lastname: Smith
mesh_terms: D000328:Adult; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D015237:Dinoprost / Q000494:pharmacology; D011464:Epoprostenol / Q000494:pharmacology; D005260:Female; D005333:Fetus / Q000098:blood supply*; D006801:Humans; D010920:Placenta / Q000098:blood supply*; D011247:Pregnancy; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D003346:Corticotropin-Releasing Hormone; D015237:Dinoprost; D011464:Epoprostenol