Efficacy of intrarenal ACE-inhibition estimated from the renal response to angiotensin I and II in humans

Efficacy of intrarenal ACE-inhibition estimated from the renal response to angiotensin I and II in humans. Recent studies on the nature of the renin-angiotensin system (RAS) in animals have led to the concept that systemic and intrarenal RAS can be influenced to different degrees by angiotensin converting enzyme (ACE) inhibitors. Assessment of efficacy of intrarenal ACE inhibition by ACE inhibitors in humans is necessarily indirect and has not been reported. We therefore monitored the renal response to acute angiotensin (Ang) I infusion in volunteers taking 20 mg enalapril twice daily, and related the responses to the obtained increments in plasma Ang II levels. Ang I infusion rates of 4, 8, 16, and 32 pmol/kg/min caused gradual increments in plasma Ang I (maximal change from 26 ± 18 to 578 ± 120 pmol/liter, P