Leptin: the link between overweight and primary hyperparathyroidism?

Primary hyperparathyroidism is one of the most common causes of hypercalcemia. Most cases result from sporadic benign monoclonal adenomas or hyperplasia. Increased body weight is consistently present in cohorts of patients with primary hyperparathyroidism. It has been shown that fat mass is the major determinant of serum parathyroid hormone levels independent of vitamin D status. Leptin, an adipocyte-derived hormone with mitogenic activity, regulates energy homeostasis and mineral metabolism. Serum leptin levels increase in parallel to the amount of adipose stores. Interestingly, a positive association between leptin and parathyroid hormone levels is observed. Patients with primary hyperparathyroidism have higher serum leptin levels than healthy subjects. In addition, leptin administration in mice increases circulating levels of parathyroid hormone. We hypothesize that leptin involves pathogenesis of primary hyperparathyroidism and represents a link between hyperparathyroidism and increased body weight.