THE EFFECT OF CALCITONIN INJECTED INTO HYPERCALCAEMIC AND NORMOCALCAEMIC PATIENTS

. Porcine calcitonin has been purified by the method of Tenenhouse et al. followed by gel filtration. Forty-five MRC units were injected i.m. or i.v. into seven hypercalcaemic and five normocalcaemic patients. Four control subjects received the vehicle for calcitonin. The serum concentrations and the urinary excretion rates of calcium, magnesium, phosphate, sodium, potassium, and creatinine were measured at short intervals for three days. The hormone was injected on the second day. Complexed and ionized calcium, alkaline phosphatase, and protein in serum were determined. The calcium turnover and bone formation rate were determined by the technique of Heaney and Whedon using 47Ca. There was a significant hypocalcaemic effect in all patients, most pronounced in the hypercalcaemic group. However, the effect seemed to be better correlated to the bone formation rate than to the degree of hypercalcaemia. A significant decrease in serum magnesium concentration was observed in the hypercalcaemic group. It was difficult to evaluate the effect on serum phosphate because of large diurnal fluctuations. An increased urinary sodium excretion rate after calcitonin administration was registered.