[Urinary excretion of cAMP after PTH injection in patients with hypohyperparathyroidism (author's transl)].

The urinary excretion of cyclic adenosine monophosphate (cAMP) and phosphate in response to an intravenous injection of 200 U.I. PTH in two women with hypohyperparathyroidism was studied. PTH activity was previously verified. Both patients were under treatment with vitamin D and their plasma calcium and phosphate levels were normal at the time of the study. Basal values for urinary excretion of cAMP were 2.25 nmol/min in one patient and 4.2 nmol/min in the other. Maximum excretion after PTH injection were 6.4 nmol/min and 5.5 nmol/min respectively. Basal values for urinary excretion of phosphate were 0.32 mg/min in the first patient and 0.18 mg/min in the second. After PTH injection the peak values were 0.73 mg/min and 0.35 mg/min respectively. These results pointed out the existence of a renal resistance to PTH which, unlike what happens in other similar patients, cannot be corrected with the administration of vitamin D.