title: Vitamin D hydroxylation in youth and old age.
abstract: The effects of the subcutaneous injections of 50 000 i.u. of vitamin D on 25-hydroxy-vitamin D levels were measured in young controls, old people living at home, and in elderly in-patients. Responses were substantially reduced in both groups of old people, particularly in those living at home. This phenomenon may be due to the effects of ageing or disease on 25-hydroxylase activity.
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging; D001711:Biotransformation; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood*; D006900:Hydroxylation; D008099:Liver / Q000378:metabolism; D008875:Middle Aged; D014807:Vitamin D / Q000008:administration & dosage*
chemical_list: D006887:Hydroxycholecalciferols; D014807:Vitamin D