POSTOPERATIVE STUDIES ON PARATHYROID-HORMONE SECRETION IN PATIENTS OPERATED ON FOR PRIMARY HYPERPARATHYROIDISM

The secretion of intact parathyroid hormone (PTH) was investigated in 11 patients operated on for parathyroid adenoma at 1 year after surger y and compared with that of seven healthy individuals and five patient s operated on because of clinical and biochemical signs of primary hyp erparathyroidism with equivocal diagnosis after surgery. The investiga tion was performed by infusing Na2EDTA and CaCl2 at constant rates. No significant difference was found in the suppressibility of PTH secret ion by calcium. The set point (the calcium concentration required for half-maximal inhibition of PTH secretion) was slightly lower in patien ts (1.20 +/- 0.02 mmol/l) compared with healthy subjects (1.23 +/- 0.0 3 mmol/l; P < 0.05). During the hypocalcemic EDTA infusion, the secret ion of PTH was higher in controls compared with patients (P < 0.01). B y comparing the data from the infusion tests in patients operated on f or parathyroid adenomas with the data obtained from the patients with equivocal diagnosis after parathyroid surgery, a good probability for the diagnosis could be obtained.