Blackwell Publishing Journal Backfiles 1879-2005
The aim of the present study was to determine the diurnal secretion of melatonin, cortisol, prolactin, calcitonin during chronic parathyroid hormone-dependent hypercalcemia. Eight women, aged 40–76 years, with primary hyperparathyroidism (PHPT) were studied before after surgical removal of a parathyroid adenoma. The hormone concentrations in blood were determined at 08, 12, 16, 22, 02, 04, 06 h. Concomitantly, the excretion of melatonin cortisol in urine between 07–19 h 19–07 h, the clearance of calcium creatinine were measured.Nyctohemeral serum prolactin calcitonin were unaffected by moderate parathyroid hormone-dependent hypercalcemia. In contrast, serum cortisol melatonin were significantly higher during active disease than after surgical cure. Mean 24-h variation of serum cortisol was 349 ± 34 nmol/liter vs. 223 ± 17 nmol/liter mean serum melatonin was 0.13 ± 0.04 nmol/liter vs. 0.06 ± 0.02 nmol/liter. Endogenous creatinine clearance was similar before after surgery, while the clearance of melatonin cortisol significantly increased after surgery, indicating an increased tubular reabsorption of both hormones during active disease. Fasting morning glucose concentrations were also significantly decreased after successful surgery, 6.1 ± 0.6 vs. 5.2 ± 0.5 mmol/liter. It is suggested that the relative hypercortisolism may be the cause of the glucose intolerance in primary hyperparathyroidism.Three to 4 months after surgical cure the serum melatonin levels were significantly lower than those seen in age-matched controls, indicating a melatonin insufficiency in patients successfully treated for PHPT. The meaning of this finding is not yet understood but might be of importance in the development of primary hyperparathyroidism.
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