[Clinical aspect of recent progress in phosphate metabolism. FGF23; physiological action and molecular mechanism in the regulation of phosphate and vitamin D metabolism].

Fibroblast growth factor (FGF) 23 is an endocrine hormone regulating the phosphate and vitamin D metabolism in the normal physiology. Recent studies have revealed that Klotho plays an essential role in FGF23 signaling. Klotho-deficient mice exhibit premature aging-like phenotypes, and therefore, this molecule has provided insights into the molecular mechanism of aging. However, it is suggested that the phenotype of the Klotho-deficient mice results from the disturbance in the phosphate and vitamin D metabolism. The importance of the FGF23/Klotho system thus is evident, but additional questions arose from this new concept.