The renin-angiotensin system. New concepts in regulation of blood pressure and renal function.

The past decade has been considerable advances in basic knowledge of the renin-angiotensin system. Perhaps the most important new development has been the appreciation of a tissue-based renin-angiotensin system that can be independently regulated from the circulation. Greater insight into the mechanism by which the renin-angiotensin system exerts its actions has been achieved through the study of molecular biology and pharmacologic characterization of multiple angiotensin receptor subtypes. Ang II is now considered a growth promoter in cardiovascular tissues, and the resultant vascular hypertrophy is an important contributor to the maintenance of hypertension. Ang II also plays a role in the kidney, not only as a regulator of hemodynamics, but in the development of structural changes (hypertrophy, sclerosis), which are important in the pathogenesis of a variety of renal disorders. Finally, a central role for the renin-angiotensin system in experimental renovascular hypertension has been reaffirmed. In the future, basic knowledge and techniques of investigation gained from experimental models will be used to investigate clinical disorders such as hypertension and various renal disorders characterized by abnormal function of the renin-angiotensin system.