Angiotensin-converting enzyme inhibitors: medicinal chemistry and biological actions.

A decade of experimentation, with work in the last four years greatly accelerated by the availability of captopril, favors the conclusion that angiotensin-converting enzyme inhibitors exert their antihypertensive effect by blocking the formation of angiotensin II. The apparently anomalous efficacy of ACE inhibitors in hypertension characterized by low circulating renin levels may point to the importance of the vascular renin-angiotensin system in controlling blood pressure. Neither kinin potentiation nor blockade of the CNS renin-angiotensin system appear to play a significant role in the antihypertensive effect of captopril. Pharmacological and clinical studies on ACE inhibitors of novel chemical structure will establish their utility as antihypertensive agents and may lead to greater understanding of the mechanism of action of all ACE inhibitors.