DEFICIENCY OF C-GMP LEVEL IN PLACENTAL CIRCULATION IN PREGNANCY-INDUCED HYPERTENSIVE DISORDERS - POSSIBILITY OF DECREASED ENDOTHELIUM-DERIVED RELAXING FACTOR ACTIVITY

Objective: To investigate the hypothesis that a decrease in the synthe sis of endothelium-derived relaxing factor (EDRF) is involved in the p athophysiology of pregnancy-induced hypertensive disorders. Methods: L evels of cyclic nucleotides and prostacyclin were measured by RTA meth ods in umbilical venous plasma, obtained from 28 women with normotensi ve pregnancy, 8 with pregnancy-induced hypertension and 8 with preecla mpsia. The sampling was done at the time of delivery. The criterion fo r hypertension was a diastolic blood pressure of 90 mm Hg or more; pre eclampsia was defined as hypertensive pressure with proteinuria (great er than or equal to 1 g/L). Statistical analysis was done by the Stude nt t test. Main Outcome Measures: Umbilical venous plasma concentratio ns of c-GMP, 6-keto-PGF(1 alpha), and c-AMP. Results: A significantly lower level of c-GMP was found in hypertensive pregnant patients compa red with normotensive women (P < 0.01), but there was no difference be tween groups with pregnancy-induced hypertension and preeclampsia. The level of 6-keto-PGF(1 alpha) in umbilical venous plasma in hypertensi ve patients was also significantly reduced (P < 0.05). Conclusions: Th e reduced c-GMP activity in umbilical venous plasma in patients with p regnancy-induced hypertensive disorders may support the hypothesis tha t a reduced production of endothelium-derived relaxing factor in the p lacental circulation may be involved in the pathophysiology of pregnan cy-induced hypertension and preeclampsia.