The effect of angiotensin converting enzyme inhibitors on isolated glomeruli

The following study was designed to examine the effect of the angiotensin converting enzyme (ACE) inhibitors captopril and enalapril on certain biological and physiological activities of isolated preparations of glomeruli from normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive SHR rats. The results suggest that the contractile response of glomeruli from SHR to exogenous angiotensin II (Ang II) is significantly enhanced by captopril whereas it has a different effect on those from normotensive (WKY) rats. These effects are unrelated to changes in glomerular Ang II binding or the level of plasma renin activity (PRA), but they do depend partially on the sodium status of the animal. Whereas captopril induced a modest increase in the basal rate of prostaglandin E2 (PGE2) synthesis by glomeruli from normotensive (WKY) but not by those from SHR, the reverse occurred in the presence of Ang II. Prostaglandin E2 synthesis was increased in both strains of rats in the presence of excess arachidonic acid. Further increases occurred with the addition of captopril, these increases being significantly greater by glomeruli from WKY rats than by those from SHR, while enalaprilat had no effect on PGE2 production. The glomerular synthesis of PGE2 was not influenced in either strain of rats by in vitro administration of captopril.