Lack of Effect of Calcitonin on the Regulation of Vitamin D Metabolism in the Rat1

Abstract

The infusion of calcitonin into intact rats increases the accumulation of 1,25-dihydroxy-[26,27-(3)(H]vitamin D)3 from 25-hydroxy-[26,27-(3)H]vita-min (D)3 in blood, but has no effect on thyropara-thyroidectomized rats using a variety of protocols. Furthermore, the vitamin D status of the animals did not alter the results. Inasmuch as no effect of calcitonin could be found on the accumulation ofother vitamin D metabolites as well as 1,25-dihydroxyvitamin D₃i t is concluded that cal-citonin apparently plays no direct role in the regulation of vitamin D metabolism and that the previous report of an effect of calcitonin on vitamin D metabolism in vivo is probably the result of a secondary response of the parathyroid glands.(Endocrinology100: 468, 1977)