Parathyroid hormone and glucocorticoids

Abstract

Antagonism between parathyroid hormone (PTH) and glucocorticoids was demonstrated in the following studies.1) The steroid therapeutic test was performed in 11 patients with primary hyperparathyroidism and also in 6 patients with hypoparathyroidism that had foods containing 500 mg of calcium and 1000 mg of phosphorus a day. The administration of prednisolone 40 mg/day caused retention of phosphorus, hypocalcemia and tetany in all patients with hypoparathyroidism while did not reveal significant changes in the concentrations of serum calcium and phosphorus in patients with primary hyperparathyroidism. No effect of prednisolone was demonstrated in the concentrations of serum calcium and phosphorus in normal subjects.2) Clearance studies were performed in intact and parathyroidectomized (PTX) dogs and the tubular reabsorption of phosphorus (TRP) was calculated in every 15 minutes. In 3 intact and 3 PTX dogs, %TRP was decreased gradually and showed minimal 75 to 90 minutes after the administration of 200 units of PTH. Infusion of 20 mg of prednisolone for 3 hours, however, demonstrated a marked prevention of a decrease of %TRP induced by PTH 200 units.3) Disappearance of 125I-PTH from serum was studied in intact dogs and it was demonstrated that infusion of prednisolone 40 mg for 3 hours induced an increase of the turnover rate of 125I-PTH with an elevation of the urinary excretion rate of 125I.