VALUE OF DIFFERENT CLINICAL AND BIOCHEMICAL CORRELATES TO ASSESS ANGIOTENSIN-CONVERTING ENZYME-INHIBITION

In a double-blind study, we compared the value of different approaches to assess blockade of angiotensin (Ang) II generation in 10 normal vo lunteers treated with the new Ang-converting enzyme (ACE) inhibitor te mocapril. Plasma concentration of the diacid active metabolite of temo capril, plasma Ang I and II levels, plasma ACE activity, and inhibitio n of the presser response to repeated intravenous (i.v.) doses of Ang I were measured before and repeatedly after different doses of temocap ril or placebo. In vivo ACE activity, estimated by the plasma Ang II/A ng I ratio, correlated well with temocapril diacid concentration (r = 0.85, n = 148) and with systolic and diastolic blood pressure (SBP, DB P) responses to Ang I(r = 0.76 and r = 0.79, n = 148). SBP and DBP res ponses to Ang I were also strongly related to temocapril diacid concen tration (r = -0.81 and r = -0.88, n = 148). ACE activity measured in v ivo reliably predicts the decrease in Ang-dependent BP to be achieved by ACE inhibitors.