title: New metabolic pathway of (24R)-24,25-dihydroxyvitamin D3: epimerization of the 3-hydroxy group.
abstract: A new metabolic pathway of (24R)-24,25-dihydroxyvitamin D3 [24,25(OH)2D3] was clarified in the in vivo experiments. After the administration of 24,25(OH)2D3 to rats, a new monoglucuronide of a vitamin D metabolite was obtained from the bile together with 24,25(OH)2D3 3- and 24-glucuronides. The genin of the metabolite was identified as 3-epi-24,25(OH)2D3 in comparison with the synthetic sample based on the data from 1H-NMR, GC/MS, and LC/atmospheric pressure chemical ionization-MS. The conjugation position was determined to be the 24-hydroxy group by the LC/electrospray ionization-MS and -MS/MS/MS combined with derivatization. To our knowledge, this is the first reported instance of the epimerization of the 3-hydroxy group of vitamin D compound with no hydroxy group at the 1alpha-position.
authors.affiliation: Faculty of Pharmaceutical Sciences, Kanazawa University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Higashi
authors.forename: R
authors.initials: R
authors.lastname: Kikuchi
authors.forename: K
authors.initials: K
authors.lastname: Miura
authors.forename: K
authors.initials: K
authors.lastname: Shimada
authors.forename: H
authors.initials: H
authors.lastname: Hiyamizu
authors.forename: H
authors.initials: H
authors.lastname: Ooi
authors.forename: Y
authors.initials: Y
authors.lastname: Iwabuchi
authors.forename: S
authors.initials: S
authors.lastname: Hatakeyama
authors.forename: N
authors.initials: N
authors.lastname: Kubodera
mesh_terms: D015650:24,25-Dihydroxyvitamin D 3 / Q000378:metabolism*; D000818:Animals; D008401:Gas Chromatography-Mass Spectrometry; D009682:Magnetic Resonance Spectroscopy; D051381:Rats
chemical_list: D015650:24,25-Dihydroxyvitamin D 3