| [ Summary ] |
We aimed to determine the serum levels of fibroblast growth factor 23 (FGF23) in patients with thyroid and parathyroid diseases to understand its physiological role in the regulation of serum phosphate homeostasis. In patients with Graves' disease, the serum FGF23 levels were significantly higher in the hyperphosphatemia group than in the normophosphatemia group or the hypophosphatemia group. Increased serum FGF23 levels were found in patients with hyperphosphatemia and hypocalcemia, caused by hypoparathyroidism after thyroidectomy. After the recovery of parathyroid function, the serum level of calcium, phosphate, and FGF23 was normalized. The serum FGF23 level was not suppressed in primary hyperparathyroidism patients, contrary to our expectations. The significant positive correlation between serum levels of phosphate and FGF23 indicates that FGF23 may play an important role in serum phosphate homeostasis by its up-regulation in the hyperphosphatemic condition. |