抄録
Endocrine effects on plasma calcium was studied in parathyroidectomized rats. Male Wistar rats parathyroidectomized by hot wire cautery were immediately given various hormonal preparations subcutaneously. In some animals adrenalectomy or thyroidectomy was performed immediately before parathyroidectomy. Blood samples were taken 6hrs. later and the plasma calcium was determined by EDTA titration method. A significant elevation of plasma calcium was observed after thyroidectomy or adrenalectomy, while a decrease in plasma calcium was found after subcutaneous injection of cortisol. No significant change of plasma calcium was seen after subcutaneous injection of ACTH, TSH, GH, lysine vasopressin, LH, corticosterone, noradrenaline, adrenaline, insulin and estrogen. Correlative investigation was further performed to compare the effects of the adrenal and thyroid on calcium metabolism with the emphasis on the hypocalcemic effect of cortisol. It was suggested that the hypocalcemic effect of cortisol was mainly due to the inhibition of intestinal absorption of calcium and not mediated by the secretion of thyrocalcitonin.
