We examined the effects of a calcium-channel blocker amlodipine on progression of renal failure in 5 of 6 nephrectomized spontaneously hypertensive rats (SHR) fed a high-salt diet. Twelve SHR, 5 of 6 with nephrectomy and salt-loading, were divided into two group: group 1 as control (n = 6) and group 2 treated with 2 mg/kg/day amlodipine (n = 6). During the 10 study weeks, body weight, systolic blood pressure (SBP), and daily urinary protein excretion were measured every 2 weeks. At the end of the study, serum creatinine, urea nitrogen, and total protein and albumin were determined. Renal tissues were obtained for light microscopic examination. The increase in SBP after 10 study weeks was significantly less in the treated group than in the control group (control 287 +/- 5 mm Hg; amlodipine 237 +/- 23 mm Hg (p < 0.01)). Urinary protein excretion was also suppressed in the amlodipine-treated group (p < 0.01). Although in the control group glomerular sclerosis and hyalinosis were marked, they were significantly less in the amlodipine-treated group. These results illustrate that amlodipine can attenuate BP increase and inhibit progression of hypertensive renal injury in this rat model.