Urinary excretion of cyclic AMP in primary hyperparathyroidism.

Urinary adenosine 3' 5' - cyclic monophosphate (cyclic AMP) was assessed by a competitive protein binding method in 19 patients with primary hyperparathyroidism (PHPT) and in 15 control subjects. The mean value of 6.6 +/- S.E. 0-64 muM per 24 hours for the patients with PHPT was higher (P less than 0-001) than the mean control value of 3-2 +/- 0-24 muM per 24 hours. In all hypercalcaemic patients without renal insufficiency, urinary cyclic AMP excretion was more than 4 muM per 24 hours and decreased in the 15 patients investigated after parathyroidectomy. In a normocalcaemic hyperparathyroid patient and in three hyperparathyroid patients with renal insufficiency, urinary cyclic AMP was less than 4 muM per 24 hours.