Radioimmunoassay of Calcitonin in Human Plasma

Abstract

Abstract A sensitive, specific radioimmunoassay of calcitonin is described, suitable for measuring the hormone in peripheral plasma of normal man. With this assay we have demonstrated that calcitonin is detectable under ba sal conditions and the concentrations respond to induced and spontaneous hypercalcemia and induced hypocalcemia. The mean value for basal calcitonin of normal men was 182 pg/ml (range 63-450); patients with hypercalcemia of various etiologies had a statistically significant higher mean value of 510 pg/ml (range 110-2700). In calcium-infusion studies, concentrations of both total calcium and ionic calcium correlated well with plasma calcitonin (0.77 and 0.84, respectively). These findings strongly suggest that calcitonin is of physiologic importance in man.