Key messages
Glucocorticoids dexamethasone and prednisolone suppress the formation of bone-derived hormone fibroblast growth factor 23 (FGF23) in vitro. The effect is accompanied by an upregulation of Dmp1, Phex, and IκBα, negative regulators of FGF23, in UMR106 osteoblast-like cells. Glucocorticoid receptor antagonist RU-486 attenuates the effect of dexamethasone on FGF23, Dmp1, and Phex. In mice, a single glucocorticoid dose suppresses FGF23 and enhances 1,25(OH)2D3 (active vitamin D).