Glycerol-induced acute renal failure (ARF) is characterized by an increase in serum creatinine, urea, and phosphate concentration, and severe impairment of creatinine clearance. Secondary hyperparaihyrohdism develops rapidly during ARF. The calcium antagonist nisoldipine clearly improves renal Junction, which becomes evident by an improvement of creatinine clearance and attenuation of the increase of serum creatinine, urea, and phosphate concentrations. Further secondary hyperparathyroidism is ameliorated by nisoldipine treatment. In spite of normalization of the hypocalcemia in ARF by nisoldipine, weak hyperparathyroidism persists, suggesting that hypocalcemia is not exclusively responsible for elevated parathyroid hormone serum levels in ARF.