Hypocalcemic effect of physiological concentrations of corticosterone in adrenalectomized-parathyroidectomized rats.

We have confirmed the serum calcium-raising effect of adrenalectomy in young male rats 5–6 h after parathyroidectomy that was first observed by others many years ago. (The phenomenon has also been reported in cats, dogs, and mice.) In addition, we have shown that adrenalectomy raises the serum ionized calcium as well as total calcium and that the effect occurs in young female as well as in young male rats. Furthermore, we have found that the serum calcium-raising effect of adrenalectomy occurs if the adrenalectomy is performed several days before parathyroidectomy or 6 h after parathyroidectomy, as well as at the same time as the parathyroidectomy. When the rats were adrenalectomized 7–9 days before parathyroidectomy and given small daily life-maintaining doses of corticosterone or cortisone acetate, this glucocorticoid treatment did not reverse the adrenalectomy effect. This led us to think at first that the effect of adrenalectomy must be due to the loss of an unknown adrenal factor rather than to loss ...