Inhibition of Tissue Angiotensin Converting Enzyme by Perindopril: In Vivo Assessment in the Rat Using Radioinhibitor Binding Displacement1

Changes in angiotensin converting enzyme (ACE) derived from plasma, lung, aorta, brain, kidney and testis were measured in rats treated with penndopril. Angiotensin converting enzyme was measured by a radio inhibitor binding method using 1251351 A. Rats were gavage fed perindopnl (1,4 and 8 mg/kg) and changes followed over 48 hr. Plasma and kidney ACE were both affected acutely with reduction of 1251351 A binding to less than 5 % of that in control animals 1 and 2 hr after gavage. Ugand binding to ACE in plasma and kidney returned to control levels after 24 hr. Ugand binding to ACE in lung, aorta and brain also was displaced after perindopril treatment. Changes were of a lesser degree than in plasma or kidney. Maximal effect was 1 to 4 hr after treatment and persisted through 24 hr postgavage. Ligand bind-ing to ACE from testis was little aftered over the time period o