Renal Excretion of Phosphate,Calcium and Sodium During and After a Prolonged Thyrocalcitonin Infusion in Man

Summary

The effect of a prolonged infusion of thyrocalcitonin on the plasma levels and urinary excretion rates of phosphate, calcium, sodium, and chloride, have been studied in man: 4 normals, 1 hyperparathyroid, and 1 hypoparathyroid. There was during the infusion and the 5 hr following it a marked rise in the excretion rate of phosphate in all the subjects except in the hyper-parathyroid. There was no change in plasma phosphate. The excretion rates of sodium, calcium, and chloride, increased in all the subjects during the first 4-7 hr of the infusion. They began to fall before the end of the infusion and reached very low values afterwards. The increased excretion of phosphate occurred without any important fall of plasma calcium or plasma phosphate and in spite of the fact that the solution infused did not contain any electrolyte. The rise in both phosphate and calcium excretion is explained by a diminished tubular reabsorption. The increased excretion of sodium and chloride is marked and prolonged. It is not possible to determine whether it is due to a diminished tubular reabsorption or to a small nonmeasurable increase in the filtered load.