Skeletal, Intestinal and Renal Calcium Dynamics in Hyperparathyroidism

The effects of parathyroid hormone on bone formation, bone resorption, intestinal absorption of calcium and renal tubular transport of calcium and phosphorus have been evaluated before and after treatment in 2 patients with parathyroid adenomas and in a third with a hyperparathyroid-like state secondary to a localized bronchogenic carcinoma. All patients underwent simultaneous 9-day balance and calcium47 kinetic studies. Renal clearances of creatinine and phosphorus were determined in all and the clearance of ultrafiltrable calcium in one. Bone formation and resorption ranged from slightly low to 4 times normal in the hyperparathyroid state. Bone resorption promptly fell after removing both parathyroid adenomas, as suggested by an immediate fall in serum calcium in 2 patients. Intestinal absorption of calcium was increased in all and promptly fell after treatment. The renal tubular reabsorption of phosphorus rose in all patients after treatment, and the renal tubular reabsorption of calcium transiently fell in the one so studied. The relative effects of hyperparathyroidism on skeletal turnover, intestinal absorption of calcium and the renal tubular reabsorption of calcium and phosphorus were variable from patient to Patient.