title: Genetic polymorphisms of xenobiotic enzymes affect human vitamin C excretion.
abstract: This study describes the effect of gene polymorphisms on the metabolism of vitamin C. An oral loading of 1 mmol ascorbic acid (176 mg) or dehydroascorbic (174 mg) was given to 17 healthy females volunteers who had consumed a low vitamin C diet (vitamin C < 5 mg/day) for 3 days before loading. The urinary total vitamin C was determined. The urinary excretion of vitamin C (VC) was compared between ascorbic acid (AsA) and dehydroascorbic acid (DAsA), and the 24 hour total VC excretion was same. However gene polymorphisms of glutathione S-transferases P1 (GSTP1) showed the effect on that excretion. GSTP1 is one of xenobiotic enzymes in VC metabolism. The VC excretions in 24 hour after VC loading were greater (P < .01) in AA homozygotes of GSTP1 (46.7 +/- 18.1 mg) than GA heterozygotes (28.2 +/- 14.0 mg). On the single oral administration, the type of polymorphisms of GSTP1 has stronger effect on VC metabolism than the form of VC, DAsA and AsA. This study showed that determination of nutrient requirement needs to be considered with personal genotype.
authors.affiliation: High Technology Center, Kagawa Nutrition University, Japan.
authors.forename: Shizu
authors.initials: S
authors.lastname: Higasa
authors.forename: Masaru
authors.initials: M
authors.lastname: Tsujimura
authors.forename: Mami
authors.initials: M
authors.lastname: Hiraoka
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nakayama
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Yanagisawa
authors.forename: Sadahiko
authors.initials: S
authors.lastname: Iwamoto
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kagawa
mesh_terms: D001205:Ascorbic Acid / Q000493:pharmacokinetics*; D003683:Dehydroascorbic Acid / Q000493:pharmacokinetics; D005260:Female; D051549:Glutathione S-Transferase pi / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D014815:Vitamins / Q000493:pharmacokinetics*; D055815:Young Adult
chemical_list: D014815:Vitamins; D051549:Glutathione S-Transferase pi; D001205:Ascorbic Acid; D003683:Dehydroascorbic Acid