Effects of PGE2 infusion on renal function in normal man before and after angiotensin II inhibition by captopril.

Increasing doses of prostaglandin E2 (PGE2) (5, 10, 20, 40, 60 ng/kg/min) were infused in 7 normal volunteers before and after angiotensin II synthesis inhibition by captopril (100 mg by mouth). PGE2 infusion alone did not alter blood pressure, while it increased the urinary excretion of both epinephrine and norepinephrine, enhanced p-aminohyppuric clearance (CPAH), inulin clearance (CIn), sodium and water excretion and decreased urinary osmolality. No changes of CIn, CPAH and catecholamines were observed after captopril alone, whilst there was a significant increase in urine output and sodium excretion and a decrease in urinary osmolality. In the presence of captopril, the infusion of PGE2 caused a significant fall in blood pressure and CIn, enhanced epinephrine excretion and sodium excretion, while it did not significantly reduce CPAH. Our findings suggest that an intact renin-angiotensin system is necessary to maintain GFR during PGE2 infusion.