Effects of parathyroid extract on metabolism of sulfate in immature rats

¹ Rockefeller Institute, New York City

Administration of parathyroid extract to immature rats that had been given S³⁵ 24 hours earlier resulted on the average in a 30% increase in the level of S³⁵ in the plasma, a 25% higher output of S³⁵ in the urine, a 17% increase in the pelt content of S³⁵, and a 14% increase in the ratio (S³⁵ in humerus ends:S³⁵ in humerus shafts), as compared with litter mates treated with an inactive control solution. The findings are interpreted as indicating that calcium mobilization induced by the action of parathyroid hormone proceeds by removal of both organic and inorganic portions of bone. Concomitant histological observations confirmed the inference drawn from the chemical analyses, namely, that administration of parathyroid extract induced a higher than normal metabolic activity in the ends of the long bones and resulted in increased bone formation and resorption.