Abstract
To assess the effects of angiotensin converting enzyme inhibitors (ACEIs) on renal function and blood pressure, we evaluated the acute effects of 5 mg of MK 421 (MK), 50 mg of SQ 14225 (SQ) and 10 mg of SA 446 (SA) on urinary excretions of sodium and potassium, of kallikrein and kinin and of prostaglandin E (UNaV, UKV, UKa1V UKinV and UPGEV), creatinine clearance (Ccr), plasma renin activity (PRA), plasma aldosterone concentration (PAC) and blood pressure in 13 essential hypertensive patients maintained with 200 mEq of sodium intake. MK, SQ and SA lowered blood pressure significantly by 10.9 mmHg, -13.5 mm Hg and -9.7 mmHg, respectively and induced diuresis and natriuresis whereas no change was found in Ccr. They also induced concomitant increases in UPGEV and UKinV and a decrease in PAC. Increases in UNaV. UPGEV and UKinV, and blood pressure reduction in SA treated group tended to be less than those in other groups whereas there were no difference in the response of PRA among the three groups. Significant positive correlations were found between the change of UKinV and of UNaV in SQ and SA treated groups and were also found between the change of UKinV and of UNaV in SQ and SA treated groups. There was no relationship between basal levels of PRA and the hypotensive effect of MK, SQ and SA, and each ACEI also lowered blood pressure even in low renin groups. These result suggest that other mechanisms than the inhibition of angiotensin II generation, such as a potentiation of bradykinin or enhanced prostaglandin formation, may contribute to their antihypertensive and renal effects.
