PREVENTION OF EXPERIMENTAL BONE ATROPHY BY THYROCALCITONIN

Abstract

In order to study the effect of thyrocalcitonin on experimental bone atrophy, male Wistar rats were placed on low Ca diet and given pre-dnisolone twice a week. Thyrocalcitonin administered in a dose of 50 MRC milliunits in a single subcutaneous injection daily caused an increase of cortical thickness of the femur and tibia and slight increase in the weight of tibia and specific gravity of both bones, but Ca and P content failed to show a marked change. Upon incubation of the metaphy-sis and diaphysis of the femur in Krebs Ringer bicarbonate buffer pH 7.4 containing 45ca at 37[degree]C for 1 hr., a significant inhibition of 45Ca uptake by the metaphysis of the femur was seen in thyrocalcitonin-treated rats. Maximal weight before breaking upon bending stress was also increased in thyrocalcitonin treated rats. These findings are consistent with the preventive effect of thyrocalcitonin on experimental bone atrophy probably through inhibition of bone resorption.