AT1 and AT2 receptors in the kidney:: Role in disease and treatment

All components of the renin-angiotensin system (RAS) are present in the kidneys and constitute a functioning renal RAS. Angiotensin II (Ang II) receptor subtypes AT(1) and AT(2) have been identified in the efferent and efferent arterioles, glomeruli, mesangial cells, and proximal tubules. Ail receptors regulate vasoconstriction and sodium and water reabsorption, as well as promote cell growth, proliferation, end collagen matrix deposition. Recent animal studies are elucidating the role of the less well understood AT(2) receptors. The AT(2) receptors appear to counterbalance the AT(1) receptors by increasing the production of bradykinin, nitric oxide, and cyclic guanosine monophosphate-mediating vasodilation and by promoting cell differentiation, antiproliferation, and apoptosis. Ang II subtype 1 receptor blockers prevent Ang II activation of the AT(1) receptor while leaving the AT(2) receptor open to Ang II stimulation. (C) 2000 by the National Kidney Foundation, Inc.