E. Schiff et al., ENDOTHELIN-1 RECEPTORS ON THE HUMAN PLACENTA AND FETAL MEMBRANES - EVIDENCE FOR DIFFERENT BINDING-PROPERTIES IN PREECLAMPTIC PREGNANCIES, Gynecological endocrinology, 7(1), 1993, pp. 67-72
Densities and affinities of tissue protein receptor sites for endothel
in-1 in placental and fetal membranes of six pre-eclamptic and 16 norm
otensive women in the 36-41th week of gestation were determined by the
use of a binding assay with [I-125]endothelin-1. The mean maximal den
sity of receptor sites (B(max)) was significantly higher in the placen
tas of the pre-eclamptic than of the normotensive women (905 +/- 107 v
s. 539 +/- 140 fmol/mg protein, p < 0.0001). No differences uere found
between the two groups with respect to the mean affinity (K(d)) of pl
acental receptors, or the mean B(max) and the mean K(d) of fetal chori
onic samples. In the normotensive group, there uere no differences in
mean placental B(max) values or in mean K(d) values between women who
went into spontaneous labor (whether delivered vaginally or abdominall
y) and those who uere electively operated on prior to labor onset. No
binding sites uere detected in the fetal amniotic membranes of any of
the women. Our results suggest that an increase in the maximal density
of receptor sites to endothelin-1 in the placenta may play a role in
the pathophysiology of pre-eclampsia by contributing to the placental
insufficiency that characterizes this disorder.