Endogenous Stimulators and Inhibitors of Prostaglandin Synthesis in Pregnancy Induced Hypertension

Abstract

The effect of endogenous factor(s) in the maternal venous serum, cord venous serum, the liquor amnii and cytosolic extracts of placentae, obtained from normal subjects (n = 29) and those with pregnancy induced hypertension (n = 12) on the conversion of arachidonic acid to prostaglandin E₂ has been investigated. The endogenous inhibitory activity in the liquor amnii at a concentration of 0.89% (v/v), the maternal venous serum and cord venous serum was identical in the two groups. The stimulatory effect of liquor amnii at a concentration of 0.02% (v/v), however, was 7% ± 10 (mean ± s.d.) in pregnancy induced hypertension when compared to 34% ± 10 in the normal subjects. In the placental cytosol the stimulatory effect on prostaglandin synthesis was significantly higher in pregnancy induced hypertension when compared to normal pregnancy (p<0.05). The possible application of these results to explain the changes in the vasoconstrictor and vasodilator prostaglandin production by the intra-uterine tissues during pregnancy hypertension is discussed.