title: 25-Hydroxyvitamin D3 1alpha-hydroxylase and vitamin D synthesis.
abstract: Renal 25-hydroxyvitamin D3 1alpha-hydroxylase [1alpha(OH)ase] catalyzes metabolic activation of 25-hydroxyvitamin D3 into 1alpha, 25-dihydroxyvitamin D3 [1alpha,25(OH)2D3], an active form of vitamin D, and is inhibited by 1alpha,25(OH)2D3. 1alpha(OH)ase, which was cloned from the kidney of mice lacking the vitamin D receptor (VDR-/- mice), is a member of the P450 family of enzymes (P450VD1alpha). Expression of 1alpha(OH)ase was suppressed by 1alpha, 25(OH)2D3 in VDR+/+ and VDR+/- mice but not in VDR-/- mice. These results indicate that the negative feedback regulation of active vitamin D synthesis is mediated by 1alpha(OH)ase through liganded VDR.
authors.affiliation: Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Takeyama
authors.forename: S
authors.initials: S
authors.lastname: Kitanaka
authors.forename: T
authors.initials: T
authors.lastname: Sato
authors.forename: M
authors.initials: M
authors.lastname: Kobori
authors.forename: J
authors.initials: J
authors.lastname: Yanagisawa
authors.forename: S
authors.initials: S
authors.lastname: Kato
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002112:Calcifediol / Q000378:metabolism; D002117:Calcitriol / Q000096:biosynthesis* / Q000378:metabolism / Q000494:pharmacology; D003001:Cloning, Molecular; D005246:Feedback; D015971:Gene Expression Regulation, Enzymologic; D007668:Kidney / Q000201:enzymology / Q000378:metabolism; D008024:Ligands; D051379:Mice; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000378:metabolism; D014162:Transfection
chemical_list: D008024:Ligands; D012333:RNA, Messenger; D018167:Receptors, Calcitriol; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase; D002117:Calcitriol; D002112:Calcifediol