Influence of the thyroids on the rate of removal of recently deposited radiocalcium and radiophosphorus from bone.

Abstract

The difference in the response of thyroid-intact (TI) and thyroidectomized rats (TX) to a single calcium injection was studied in this report. Four experimental series were included: 1) comparison of TI and TX rats, both groups containing functional parathyroid transplants in the cornea; 2) the same but with prior nephrectomy; 3) comparison between the 2 groups (TX and TI), with the calcium injected 12 hr following parathyroidectomy; and 4) the same except that the rats were maintained on a phosphate-deficient diet 3 days prior to use. Three comparisons were made between TX and TI rats: 1) the effect of calcium challenge on subsequent plasma calcium and phosphate changes; 2) the effect on plasma levels of 32P and 45Ca, the isotopes having been administered 10 days prior to calcium challenge; and 3) the effect on plasma levels of 32P and 45Ca which had been administered only 12 hr prior to use. The following observations were made: 1) Both plasma calcium and phosphate levels rise after calcium injection in...