title: [Vitamin D metabolism and action].
abstract: Vitamin D is either produced in the skin by exposure to UVB radiation or is ingested in the diet, and then is converted to 25-hydroxyvitamin D (25OHD) in the liver. 25OHD is then taken up by renal proximal tubule epithelial cells via megalin-dependent endocytosis, and is subjected to 1alpha-hydroxylation to produce 1,25-dihydroxyvitamin D [1,25 (OH) (2)D] , an active form of vitamin D. 1,25 (OH) (2)D exerts various effects via nuclear vitamin D receptor (VDR) in target organs, including kidney, intestine and bone. Recently, much attention is paid to the roles of FGF23 and Klotho, both of which are molecules critical in phosphate homeostasis, in vitamin D metabolism.
authors: Osaka Medical Center and Research Institute for Maternal and Child Health, Department of Bone and Mineral Research.
authors: Toshimi
authors: T
authors: Michigami
mesh_terms: D000818:Animals; D000089703:Fibroblast Growth Factor-23; D006801:Humans; D018167:Receptors, Calcitriol / Q000502:physiology; D014807:Vitamin D / Q000031:analogs & derivatives / Q000378:metabolism / Q000502:physiology*
chemical_list: C000717427:FGF23 protein, human; D018167:Receptors, Calcitriol; D014807:Vitamin D; C097949:1,25-dihydroxyvitamin D; D000089703:Fibroblast Growth Factor-23; C104450:25-hydroxyvitamin D