Placental Urocortins and CRF in Late Gestation

• Published in: Placenta (Eastbourne) Vol. 30; no. 6; pp. 483 - 490
• Main Authors: Pepels, P.P.L.M, Spaanderman, M.E.A, Bulten, J, Smits, P.B.A.M, Hermus, A.R.M.M, Lotgering, F.K, Sweep, C.G.J
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.06.2009; Elsevier
• Subjects: Amnion; Biological and medical sciences; Birth; Chorion; Corticotropin-Releasing Hormone - analysis; Corticotropin-Releasing Hormone - metabolism; CRF; CRH; Embryology: invertebrates and vertebrates. Teratology; Extraembryonic Membranes - metabolism; Female; Fundamental and applied biological sciences. Psychology; Gestational Age; Humans; Immunohistochemistry; Internal Medicine; Labor; Membranes; Obstetrics and Gynecology; Placenta; Placenta - metabolism; Placental clock; Pregnancy; Pregnancy Trimester, Third - metabolism; RIA; Tissue Distribution; Ucn; Urocortin; Urocortins - analysis; Urocortins - metabolism; Immunohistochemistry; Ucn; Membranes; RIA; Chorion; Birth; Labor; Urocortin; Placenta; CRF; CRH; Amnion; Placental clock; Hypothalamic hormone; Pregnancy; Vertebrata; Late; Mammalia; Fetal membrane; Corticotropin releasing factor; Hormone releasing factor
• ISSN: 0143-4004; 1532-3102
• DOI: 10.1016/j.placenta.2009.03.008

Abstract Placental corticotropin-releasing factor (CRF) are thought to induce labor via activation of CRF receptor type 1 (CRF-R1) leading to several feed forward mechanisms in the placental, fetal and maternal compartments. Recently, receptor type 2 (CRF-R2) selective ligands called urocortin 2 and 3 (Ucn 2, Ucn 3) were characterized as neuropeptides in the brain. We studied the expression of Ucn 1, 2 and 3 in feto-placental tissues qualitatively (by immunohistochemistry) and quantitatively (by radioimmunoassay) and compared these with expression of placental CRF. The presented placental Ucn 2 and 3 peptide quantification, characterization and ex-vivo release results are novel. Reversed-phase HPLC fractionation of placental extracts revealed several peaks containing immune-reactive (ir)-like Ucn 2 or 3, of which the main peaks had the same retention time as the synthetic Ucn 2 and 3 peptides. Placental tissues contained between 6 and 10 times more ir-CRF than ir-Ucn 1, 2 or 3. The placental Ucn 1, 2 and 3 peptide contents correlated with each other. Our immunohistochemical results showed that all urocortins were mainly localized in the syncytiotrophoblasts of the placental villi. Placental urocortins were actively released during ex-vivo perfusion of cotyledons. From these results it can be concluded that Ucn 2 and 3 peptides are present in placental and fetal membrane tissues, and released by ex-vivo perfused cotyledons. Therefore, placental urocortins may function as paracrine or endocrine messengers during pregnancy and parturition.