Calcitonin secretion in primary hyperparathyroidism.

Plasma calcitonin (CT) was studied by RIA in 55 patients with surgically proven primary hyperparathyroidism. Basal hormone measurements were performed in all patients and provocative tests of CT secretion were performed in 7. Biochemical measurements were also made before and after parathyroidectomy in 34 patients. Plasma CT was significantly increased above normal in the male but not the female group of patients with primary hyperparathyroidism. A similar sex difference in plasma CT was also seen during provocative testing. In contrast to normal subjects, plasma CT was also significantly correlated to serum calcium concentration in the males but not the females. Hormone concentrations returned to normal after parathyroidectomy in the males and did not significantly change in the females. These studies demonstrate that some patients with primary hyperparathyroidism, especially males, may have an increase, perhaps compensatory, in plasma CT. As with normal females, females with primary hyperparathyroidism seem to have decreased CT reserve.