Effect of Parathyroid Hormone and Sodium Acid Phosphate on Bones of Guinea Pigs. ∗

Abstract

When parathyroid hormone is administered to normal subjects there is a rise in the serum calcium and a decrease in the serum phosphorus. Albright and Ellsworth believed that, following the administration of parathyroid hormone, the body fluids became depleted of phosphorus as evidenced by falling serum phosphorus; the tendency to make up the deficiency of the phosphorus and consequently the phosphate ions in the blood serum was met by removing calcium phosphate from the bones and a rise in the serum calcium ensued.

The recognition of the relationship of decalcification of bone in clinical hyperparathyroidism (fibrous osteodystrophy) and the experimental production of similar lesions by the use of the hormone of the parathyroid gland have interested us in the study of the effect of simultaneous injections of phosphate and parathyroid hormone. Three groups of growing guinea pigs whose average weight was 215 gm. were employed. One group of 3 animals received increasing daily doses of parathyroid hormone beginning with 5 units and were injected for 25 days. The second group received daily increasing doses of Na₂HPO₄.12H₂O in aqueous solution so that 1 cc. of the solution equaled 0.075 gm. of Na₂HPO₄ or 0.05 gm. of PO₄ or 0.0163 gm. of P. The injections were made daily into the peritoneal cavities, beginning with 1/4 cc. and gradually increasing the dose to 1 cc. Preliminary injections had shown that a dose of over 1 cc. was rapidly fatal. The third group received subcutaneous injections of parathyroid hormone and intraperitoneal injections of the phosphate solution simultaneously. The doses were given in the same amount as that administered to the control groups. The diet allowed the animals was the same as that given our regular stock guinea pigs and consisted of white bread, leafy greens, hay and oats.