Effects of captopril on prostaglandin and natriuresis in patients with essential hypertension.

The antihypertensive, renal and hormonal effects of captopril were studied in 10 patients with essential hypertension. Captopril significantly decreased arterial blood pressure with a concomitant increase in glomerular filtration rate, natriuresis and kaliuresis and a significant selective increase in urinary (renal) prostaglandin E2; other plasma and urinary prostaglandin (F2 alpha, 6-keto-prostaglandin F1 alpha; thromboxane B2) were not significantly changed. The urinary prostaglandin E2 increase was observed even in patients with pretreatment subnormal prostaglandin E2 excretion. Increases in urinary prostaglandin E2 were significantly positively correlated with increases in urinary sodium concentration. It is concluded that the antihypertensive effect of captopril is mediated, at least partially, by prostaglandin E2 release from renal and extrarenal tissues. Captopril enhances natriuresis at a lower perfusion pressure.