[FGF23, a "new" hormone regulating phosphate homeostasis and vitamin D metabolism].
Until recently, the action of two hormones - parathyroid hormone (PTH) and calcitriol - on three target tissues - bone, kidney, and gut - has been thought to regulate the closely linked homeostasis of calcium and phosphates. In this system, an increase in the plasma concentration of one ion often leads to a reciprocal change in the concentration of the other and PTH stimulates 1 alpha-hydroxylase activity and calcitriol synthesis in renal proximal tubular cells. A second phosphate regulation system was recently identified. It involves one or more phosphaturic hormones, called "phosphatonins", that is, circulating factors with potent phosphaturic activity. The key phosphatonin appears to be a fibroblast growth factor, known as FGF23. It is now established that FGF23 regulates not only phosphate homeostasis, but also vitamin D metabolism. In contrast to PTH, however, FGF23 inhibits rather than stimulates 1 alpha-hydroxylase activity and calcitriol synthesis.
Silve
C
C
Inserm U 683, Faculté de médecine Xavier Bichat, 75018 Paris. silve@bichat.inserm.fr
D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D006706:Homeostasis; D006801:Humans; D010281:Parathyroid Hormone / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism*; D014807:Vitamin D / Q000378:metabolism*
C000717427:FGF23 protein, human; D010281:Parathyroid Hormone; D010710:Phosphates; D014807:Vitamin D; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23