Renal effects of perindoprilat, an angiotensin-converting enzyme inhibitor, in the anesthetized dog

The effects of perindoprilat on renal hemodynamics and the elimination of water and electrolytes were studied acutely in the anesthetized dog. Two groups of animals were compared, one on normal sodium and water, the other on an acutely restricted sodium and water diet. In all cases, perindoprilat injected into renal artery (0.1 and 0.5 mg/kg) reduced blood pressure. In the animals on a low sodium diet, perindoprilat increased renal blood flow from 2.2 +/- 0.3 to 2.9 +/- 0.3 ml/min/g and decreased the filtration fraction; the decrease in renal vascular resistance predominated on the efferent arteriole of the glomerule (45% decrease), preferential site for the vasoconstrictor action of angiotensin II. In the animals on a normal sodium diet, renal blood flow was also increased from 4.1 +/- 0.6 to 5.1 +/- 0.6 ml/min/g but without the filtration fraction being affected. The renal vascular resistance was decreased at both pre- and post-glomerular levels (respectively, 50 and 25% decrease). After sodium and water restriction, but not in animals on a normal sodium diet, perindoprilat increased the fractional elimination of water and electrolytes. This salidiuresis might be accounted for by the hemodynamic effect of converting enzyme inhibitor and the decrease it elicits in filtration fraction, modifying sodium and water reabsorption in the proximal tubule.