Influence of pharmacological doses of calcitonin on serum beta 2 microglobulin concentration

The effect has been studied of continuous infusion of calcitonin in 14 hypercalcemic patients and 5 patients with Paget's disease of the bones. In all hypercalcemic patients but one, a good serum calcium lowering effect was obtained. In all subjects there was a significant decrease of serum beta 2 microglobulin concentration during calcitonin infusion (4.1 +/- 3.4 vs 2.9 +/- 2.5 mg . l-1; P less than 0.01). Especially in patients with an initial increased serum beta 2 microglobulin, a pronounced decrement of this serum beta 2 microglobulin was achieved. Moreover, a positive correlation was found between the drop in serum calcium concentration and the serum beta 2 microglobulin concentration before calcitonin infusion (r = 0.83; P less than or equal to 0.01). Urinary beta 2 microglobulin excretion did not change significantly during calcitonin infusion. These results led to the speculation that the serum calcium lowering effect of calcitonin is not only the result of the direct antiosteoclastic effect of this hormone but that some immunologic modulating effect of calcitonin on the monocyte macrophage system of the bones is contributory to this hypocalcemic effect of calcitonin.