Renal responses to angiotensin receptor antagonist and angiotensin-converting enzyme inhibitor in partially nephrectomized spontaneously hypertensive rats.

To investigate the role of the renin-angiotensin system (RAS) on nephrosclerosis in salt-loaded, partially nephrectomized spontaneously hypertensive rats (SHR), we evaluated the effects of angiotensin II (ANGII) blockade on the progression of nephrosclerosis with an angiotensin type 1 receptor (AT1rec) antagonist [TCV-116 (TCV)] and an angiotensin-converting enzyme (ACE) inhibitor (enalapril) at the doses equivalent in reducing systemic blood pressure (BP). SHR were five/sixths nephrectomized and were fed a high-salt diet. In addition to being significantly preventive against an increase in systolic BP, both TCV and enalapril significantly attenuated the increases in proteinuria and the renal histopathological alterations. Transcription of AT1rec mRNA in the remnant kidney was enhanced with the progression of nephrosclerosis, but was inhibited by TCV as well as enalapril. In these aspects, there were no apparent differences between effects of TCV and enalapril. The RAS system plays an important role in nephrosclerosis in partially nephrectomized SHR despite a high-salt diet, and direct ANGII blockade certainly protected the kidney against hypertensive injury in this model.