Effects of parathyroid hormone and calcitonin on plasma and nephrogenous cyclic adenosine-3',5'-monophosphate in normal subjects and in pathological conditions.

To evaluate the response of bone cells and kidney to parathyroid hormone (PTH) and calcitonin (CT), the acute effects of these hormones given intravenously on plasma cyclic adenosine 3',5'-monophosphate (cAMP), nephrogenous cAMP and clearance ratio (cAMP:creatinine), have been studied in normal subjects and in patients with Paget's disease, hypoparathyroidism and osteopetrosis. Twenty-five subjects were given bovine synthetic PTH, thirty-eight calcitonin (sixteen salmon, eighteen human and four porcine CT). In normal subjects and in patients with Paget's disease and hypoparathyroidism plasma cAMP increased within 1 h following PTH intravenous infusion. The same dose of PTH failed to produce any increase in plasma cAMP level in two children with marble bone disease. Nephrogenous cAMP increased in all cases. A different relative potency of calcitonins in increasing plasma cAMP has been observed in normal subjects, according to previous results on the plasma calcium lowering effect. Paget's disease patients showed a greater increase in plasma cAMP following infusion than normal subjects. The measurement of nephrogenous cAMP and the clearance ratio (cAMP: creatinine) demonstrated a minor involvement of the kidney in the production of cAMP after CT infusion; the late increase observed in nephrogenous cAMP was probably due to a parathyroid rebound following the hypocalcemic effect of CT.