Vascular renin-angiotensin system in hypertension. New insights into the mechanism of action of angiotensin converting enzyme inhibitors.

Evidence is accumulating that demonstrates the presence of local renin-angiotensin systems, in addition to the established circulating renin-angiotensin system. Renin-like substances, immunoreactive angiotensins, and angiotensin II receptors have been identified throughout the vasculature. Local tissue concentrations of angiotensin converting enzyme (ACE) inhibitors, rather than serum concentrations, may be more important in determining the magnitude and duration of the long-term cardiac and vascular response to this group of drugs. Certain structural and chemical properties of the ACE inhibitors may provide unique effects at various tissue sites.