The urine cyclic AMP response to parathyroid extract (PTE) administration in normal subjects and patients with parathyroid dysfunction

Abstract

Fourteen normal subjects, 21 patients with primary hyperparathyroidism, and 12 patients with hypoparathyroidism were studied to evaluate the effects of an excess or deficiency of endogenous parathyroid hormone (PTH) and of serum calcium and phosphate upon urinary cyclic AMP and phosphate responses to PTE administration in man. Preoperatively, the hyperparathyroid patients were hypercalcemic and hypo- or normophosphatemic; post-operatively, they were hypo- or eucalcemic and euphosphatemic. The hypoparathyroid patients were hypocalcemic and hyperphosphatemic. Hourly urine specimens were collected from 8:00 a.m. to 12:00 noon on two consecutive days and analyzed for their cyclic AMP, phosphate, and creatinine contents. On the second day, 200 USP units of PTE were administered intravenously over a period of 5 min beginning at 9:00 a.m. Cyclic AMP excretion in the control period, prior to PTE infusion, was significantly elevated in the hyperparathyroid patients preoperatively, but fell to normal postoperatively, and was significantly depressed in the hypoparathyroid patients. Phosphate excretion during the same control period was significantly elevated to near maximal levels in the hyperparathyroid patients preoperatively, but fell to normal postoperatively and was not significantly different from normal in the hypoparathyroid patients. Following PTE administration, the same maximal levels of cyclic AMP and phosphate excretions were observed in all of the groups studied. Thus, there were no apparent effects of endogenous PTH levels or serum calcium and phosphate levels on the maximum excretion rates of cyclic AMP or phosphate following PTE administration in patients with hyper- or hypoparathyroidism.