Endothelin transfer and endothelin effects on water transfer in human fetal membranes.
Although endothelin-1 is synthesized by human amnion, its physiologic role and its ability to be transferred to myometrium for oxytocic action remain unclear. We investigated the transfer of endothelin-1 itself and the effects of endothelin-1 on the transfer of tritiated water across human amnion or amnion/chorion/decidua in vitro with an Ussing chamber technique. Permeability coefficients (mean +/- standard error) for 3H2O across amnion/chorion/decidua in the fetal to maternal direction were 1.26 +/- 0.21 and 1.25 +/- 0.10 x 10(-4) cm/second (N = 6) and in the maternal to fetal direction 0.90 +/- 0.07 and 0.98 +/- 0.15 x 10(-4) cm/second (N = 5) in the absence or presence, respectively, of 10(-9) mol/L endothelin-1 in the fetal reservoir. Comparable values were found in either direction with 10(-9) mol/L endothelin-1 in the maternal reservoir. Apparent permeability coefficients for 125I endothelin-1 in the fetal to maternal direction were 3.34 +/- 0.79 and 2.43 +/- 0.68 x 10(-5) cm/second (N = 5) for amnion or amnion/chorion/decidua. However, appreciable trapping of 125I endothelin-1 by the fetal membranes was apparent. Endothelin-1 does not appear to affect water movement across the human fetal membranes, and only a small proportion of endothelin-1 itself is transferred across the membranes.
Eis
A W
AW
Department of Obstetrics and Gynecology, University of Cincinnati College of Medicine, Ohio.
Mitchell
M D
MD
Myatt
L
L
D001692:Biological Transport; D016232:Endothelins / Q000378:metabolism / Q000502:physiology*; D005321:Extraembryonic Membranes / Q000378:metabolism*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008431:Maternal-Fetal Exchange; D010539:Permeability; D011247:Pregnancy; D014867:Water / Q000378:metabolism*
D016232:Endothelins; D014867:Water