title: Endothelin-1 levels in the maternal-fetal dyad.
abstract: The aim of this study was to determine the distribution of ET-1 levels in the term maternal-fetal dyad. We also compared the levels of ET-1 between umbilical vessels and assessed the effect of labor on the concentration of ET-1. The ET-1 levels were measured in plasma from 18 term maternal-infant pairs. Amniotic fluid ET-1 levels were also measured in 9 of these pregnancies. The ET-1 levels were determined by radioimmunoassay (RIA) after extraction of plasma using Sep-Pak C18 cartridges. There were no significant differences in the ET-1 levels between the umbilical artery and vein. However, there were significant differences in the umbilical artery concentration in women who labored when compared with those delivered without labor (6.0 +/- 1.1 vs. 2.7 +/- 0.7 pg/ml; t test, p = 0.022). ET-1 levels were lowest in the maternal plasma (0.9 +/- 0.2 pg/ml) and highest in the amniotic fluid (83 +/- 15 pg/ml). Assuming that elevated plasma ET-1 levels reflect increased bioactivity, the higher mean ET-1 levels in the cord vessels and in the amniotic fluid when compared to maternal levels suggest a role for ET-1 in the regulation of the fetoplacental circulation and in the constriction of blood vessels in the uterus after parturition. The higher levels of ET-1 in the umbilical artery of women who underwent labor implies that ET-1 is released as a result of the stress of labor.
authors.affiliation: Department of Obstetrics and Gynecology, Maimonides Medical Center, Brooklyn, N.Y. 11219, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Bracero
authors.forename: M R
authors.initials: MR
authors.lastname: Reale
authors.forename: M N
authors.initials: MN
authors.lastname: Te
authors.forename: G A
authors.initials: GA
authors.lastname: Zeballos
authors.forename: H S
authors.initials: HS
authors.lastname: Dweck
mesh_terms: D000653:Amniotic Fluid / Q000378:metabolism; D016232:Endothelins / Q000097:blood / Q000378:metabolism*; D005260:Female; D005333:Fetus / Q000378:metabolism*; D006801:Humans; D007743:Labor, Obstetric / Q000502:physiology; D011247:Pregnancy; D014469:Umbilical Arteries / Q000378:metabolism; D014471:Umbilical Veins / Q000378:metabolism
chemical_list: D016232:Endothelins