Authors: Nakai K, Komaba H, Fukagawa M
Fibroblast growth factor 23 (FGF23) is a recently identified bone-derived hormone that regulates phosphate and 1,25-dihydroxyvitamin D metabolism. FGF23 principally acts in the kidney to induce urinary phosphate excretion and suppress 1,25-dihydroxyvitamin D synthesis in the presence of FGF receptor 1 (FGFR1) and its coreceptor Klotho. FGF23 also acts in the parathyroid to decrease parathyroid hormone synthesis and secretion. In patients with chronic kidney disease (CKD), circulating FGF23 levels are progressively increased to compensate for persistent phosphate retention, but this results in reduced renal production of 1,25-dihydroxyvitamin D and leads to hypersecretion of parathyroid hormone. In patients undergoing dialysis, FGF23 levels are mar...