Newly recognized components of the renin-angiotensin system: Potential roles in cardiovascular and renal regulation

The renin- angiotensin system ( RAS) is a coordinated hormonal cascade in the control of cardiovascular, renal, and adrenal function that governs body fluid and electrolyte balance, as well as arterial pressure. The classical RAS consists of a circulating endocrine system in which the principal effector hormone is angiotensin ( ANG) II. ANG is produced by the action of renin on angiotensinogen to form ANG I and its subsequent conversion to the biologically active octapeptide by ANG- converting enzyme. ANG II actions are mediated via the ANG type 1 receptor. Here, we discuss recent advances in our understanding of the components and actions of the RAS, including local tissue RASs, a renin receptor, ANG- converting enzyme- 2, ANG ( 1 - 7), the function of the ANG type 2 receptor, and ANG receptor heterodimerization. The role of the RAS in the regulation of cardiovascular and renal function is reviewed and discussed in light of these newly recognized components.