Inhibition of Vitamin D<sub>3</sub> Action on Serum Calcium Concentration in Rats Treated with Stannous Chloride

Abstract

The effect of vitamin D3 (25μg/100g body wt.) on the concentration of calcium in serum of rats was investigated after a single intraperitoneal administration of stannous chloride (Sn 3.0mg/100g). The administration of vitamin D3 to normal rats increased significantly the concentration of calcium in serum, while the administration of vitamin D3 to rats treated with stannous chloride did not enhance the concentration of calcium in serum. The predominant increase in kidney calcium concentration induced by the administration of stannous chloride was significantly decreased by the injection of sodium citrate (20mg/100g) to the tin-treated rats. The amount of tin accumulated in kidney of the tin-treated rats was not altered by sodium citrate. The decreased serum calcium concentration produced by the administration of stannous chloride was significantly enhanced by the treatment of sodium citrate, and the hypercalcemic effect of vitamin D3 in the tin-treated rats exhibited approximately 50% of the value obtained from the case of normal rats. On the other hand, the administration of stannous chloride markedly elevated the concentration of inorganic phosphorus in serum, and then the color of the kidneys changed into white. The data obtained from the present experiments seem to be consistent with the point of view that the reduction of serum calcium induced by the administration of stannous chloride is caused by the disturbance of kidneys as a result of accumulation of calcium in kidneys.