The aim of the study is to compare the results of a parathyroid hormone (PTH)suppression test using a single oral tablet of cinacalcet in two groups of subjects: 1- a group of healthy adults in whom the results of the test with cinacalcet will be compared with those of the standardized PTH suppression test with intravenous calcium loading; 2- a group of patients with proven primary hyperparathyroidism in whom the results of the test with cinacalcet will be compared with those obtained during the same test, in healthy controls.

Inclusion Criteria:

• Control group: healthy adult (>18 years), having signed informed consent, taking no treatment, with effective contraception in unmenopausal women, with normal clinical examination, with normal plasma PTH, calcium, phosphorus, 25 OH vitamin D levels, with normal renal function, with normal 24 hour calciuria.
• Primary hyperparathyroidism group: adult patients (>18 years), having signed informed consent, with effective contraception in unmenopausal women, taking no treatment known to modify calcium-phosphorus status, with normal BMI, in which the diagnosis of primary hyperparathyroidism was confirmed on plasma PTH, calcium, phosphorus, 25 OH vitamin D levels, with normal renal function, with 24 hour calciuria higher than normal.

Exclusion Criteria:

• Control group: significant medical or surgical history, creatinine clearance <60 ml/min, liver insufficiency, arterial hypertension, psychiatric disorder able to modify the compliance to the study, tobacco intoxication, taking a treatment known to modify calcium-phosphorus status, severe known allergy, pregnant women, unmenopaused women without contraception.
• Primary hyperparathyroidism group:secondary hyperparathyroidism, creatinine clearance <60 ml/min, liver insufficiency, psychiatric disorder able to modify the compliance to the study, tobacco intoxication, taking a treatment known to modify calcium-phosphorus status, severe known allergy, pregnant women.