Mechanism of action of angiotensin-converting enzyme (ACE) inhibitors in hypertension and heart failure. Role of plasma versus tissue ACE.

The contribution of plasma versus tissue angiotensin-converting enzyme (ACE) to pathophysiology and drug effect is reviewed. The data suggest that tissue ACE is important in influencing local angiotensin levels and that the long term response to an ACE inhibitor is dependent on its action on tissue ACE. The tissue penetration and distribution of various ACE inhibitors may determine their duration of action and the relative effects on different organs, thereby influencing regional blood flow and tissue function. This concept of tissue ACE has improved our understanding of the mechanisms of action of ACE inhibition in the treatment of hypertension and heart failure.