FETAL VASCULAR ATRIAL-NATRIURETIC-PEPTIDE RECEPTORS IN HUMAN PLACENTA- ALTERATION IN INTRAUTERINE GROWTH-RETARDATION AND PREECLAMPSIA

OBJECTIVE: Our purpose was to quantify fetoplacental vascular atrial n atriuretic peptide receptor subtypes in human pregnancies complicated by intrauterine growth retardation or preeclampsia and to relate these parameters to the fetoplacental vascular impedance as assessed by Dop pler velocimetry. STUDY DESIGN: Guanylate cyclase-coupled and uncouple d receptors were quantified by radioligand-binding methods in membrane fractions prepared from primary and secondary stem villous vessels. D ata for 16 abnormal pregnancies delivered preterm were compared with t hat for six gestationally matched preterm controls. RESULTS: The numbe r of guanylate cyclase-coupled receptors was significantly (p < 0.001) greater in pregnancies complicated by intrauterine growth retardation or preeclampsia irrespective of normal or abnormal umbilical artery D oppler blood flow velocity pattern. The number of guanylate cyclase-un coupled receptors was unaltered. CONCLUSIONS: Because fetal plasma atr ial natriuretic peptide concentration is normal or elevated in intraut erine growth retardation and preeclampsia, these data suggest that atr ial natriuretic peptide-mediated fetoplacental vasodilation is augment ed in these disorders even in the presence of increased vascular resis tance within the fetoplacental unit.