title: Problems relating to the definition of an international unit for vitamin D and its metabolites.
mesh_terms: D002762:Cholecalciferol / Q000378:metabolism / Q000592:standards; D004097:Dihydrotachysterol / Q000592:standards; D004872:Ergocalciferols / Q000378:metabolism / Q000592:standards; D006801:Humans; D006887:Hydroxycholecalciferols / Q000378:metabolism; D006914:Hydroxysteroids / Q000139:chemically induced / Q000378:metabolism; D008970:Molecular Weight; D009751:Nutritional Requirements; D014807:Vitamin D / Q000378:metabolism / Q000592:standards*
chemical_list: D004872:Ergocalciferols; D006887:Hydroxycholecalciferols; D006914:Hydroxysteroids; D014807:Vitamin D; D002762:Cholecalciferol; D004097:Dihydrotachysterol