[FGF23 and osteonetwork].

Fibroblast growth factor 23(FGF23)is produced mainly by osteocytes and works as a hormone that reduces serum phosphate level in a Klotho-dependent manner. The identification of FGF23 revealed that bone works as an endocrine organ. On the other hand, FGF23 has been shown to be high in patients with chronic kidney disease and suggested to cause several adverse events including left ventricular hypertrophy and impaired immune function in a Klotho-independent manner. However, it is not known how FGF23 can work without Klotho.