Influence of an alpha-1-adrenoceptor antagonist, nicergoline, on placental prostanoid production in streptozotocin-induced diabetic pregnant rats

The aim of this study was to determine if placental prostanoids could mediate the vasodilating action of an alpha- 1-adrenoceptor antagonist, nicergoline (400 μg/kg i.p.), during late pregnancy in streptozotocin-induced diabetic rats (40 mg/kg i.v.). Placental prostanoid concentrations were evaluated by radioimmunoassay. Prostaglandin E2 levels showed a highly significant increase in diabetic and nondiabetic rats treated with nicergoline (p < 0.001). 6-Keto-PGF1α concentrations were slightly increased in diabetic rats compared to controls, and this increase was reversed by both nicergoline and insulin treatments. In all groups studied thromboxane B2 levels were comparable. It is concluded that prostaglandin E2 could mediate the vasodilating action of nicergoline on the placental irrigation and, therefore, improved the hemodynamic state of this organ in diabetic rats.