[Effect of calcium antagonists (nifedipine) on nephrocalcinosis and calcium excretion in the rat].

An animal model was established to test the effect of a calcium antagonist on nephrocalcinosis, which was induced by an atherogenous diet, and its effect on the excretion of calcium and other parameters relevant for stone formation. With the administration of nifedipine (Adalat), the grade of nephrocalcinosis could be significantly reduced. Furthermore, with nifedipine the excretion of calcium and sodium in the urine was raised, while phosphate and potassium levels were lowered. The excretion of magnesium and citrate, reduced by an atherogenous diet, could be raised significantly with the administration of nifedipine. The pathophysiological mechanisms underlying the effect of nifedipine on nephrocalcinosis and on the excretion of the urine parameters are discussed. Apparently hypercalciuria is the result of a reduced reabsorption of calcium in the tubulus. The inhibitory effect on the genesis of nephrocalcinosis is possibly due to the lower calcium influx into the tubular cells.