Tissue-specific activation of cardiac angiotensin converting enzyme in experimental heart failure.

Abstract
In addition to the circulating renin-angiotensin system, recent data demonstrate the existence of tissue renin-angiotensin systems that may be important in cardiovascular homeostasis. However, the relative activities of the circulating and tissue renin-angiotensin systems have not been examined previously in pathophysiological states, such as congestive heart failure. The present study was performed to examine the status of plasma and tissue angiotensin converting enzyme (ACE) activities in compensated experimental heart failure induced by coronary artery ligation in the rat. Three groups of male Sprague-Dawley rats were examined: 1) nonoperated rats (NO, n = 5), 2) sham-operated rats (SO, n = 5), and 3) heart failure rats (HF, n = 11). Rats were studied an averaged of 85 days postoperatively. In HF animals, plasma renin concentration and serum ACE activities were not different compared with NO and SO control animals. Cardiac ACE activity was 50% greater in the right ventricle than the interventricular se...