Prostaglandin E2 attenuates the pressor response to angiotensin II in pregnant subjects but not in nonpregnant subjects.

The effect of prostaglandin E2 (PGE2), 5 microgram/min-1, on the pressor response to exogenous angiotensin II (AII) has been examined in 22 women in second-trimester pregnancy and in 10 nonpregnant control subjects. PGE2 diminished the diastolic pressor response in both groups without altering basal blood pressure. This effect was significant in the pregnant group, and not significant in the nonpregnant patients. The effect was achieved by a significant increase in threshold to AII, rather than an alteration in the slope of the dose-response curve. Five pregnant patients who were given two identical infusion regimes of AII without PGE2 showed no diminution of response. The effect of PGE2 was greatest in the pregnant women who showed greatest initial sensitivity to AII, perhaps suggesting a relative deficiency of E series prostaglandins in some women by midtrimester pregnancy.