Reduction of placental nitric oxide synthase activity in pre-eclampsia

Abstract

1. The role of the potent vasodilator nitric oxide in the pathogenesis of pre-eclampsia is unclear. We have tested the hypothesis that placental activity of the enzyme which synthesizes nitric oxide (nitric oxide synthase) is reduced in pre-eclampsia. 2. Placentae were obtained after vaginal delivery or Caesarean section from women who had been assigned to the following groups according to standard obstetric criteria: term non-pre-eclamptic control, term pre-eclamptic, preterm non-preeclamptic control and preterm pre-eclamptic. Nitric oxide synthase activity of placental tissue homogenates was assessed by measuring conversion of [3H]L-arginine into [3H]L-citrulline in the presence of NADPH, ..