title: Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on vitamin A metabolism in mice.
abstract: This study aimed to clarify the effects of single and repeated administration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the activities or expression of some metabolic enzymes of retinoids and the influence of supplemental vitamin A on changed vitamin A homeostasis by TCDD. In Experiment I, the mice were given a single oral dose of 40 mug TCDD/kg body weight, with or without continuous administration of 2,500 IU vitamin A/kg body weight/day, and were killed on day 1, 3, 7, 14, and 28. In Experiment II, the mice were daily given 0.1 microg TCDD/kg body weight, with or without supplemental 2,000 IU vitamin A/kg body weight, and were killed on day 14, 28, and 42. In both experiments, TCDD significantly decreased the hepatic all-trans-retinol level and increased the hepatic all-trans-retinoic acid (RA) content, increased the mRNA and enzymatic activities of retinal oxidase. In TCDD + vitamin A mice, the all-trans retinol content was significantly higher, and the retinal oxidase mRNA was significantly lower on day 3 or 7 in Experiment I and on day 14 in Experiment II, compared to TCDD-treated mice. The induction of the retinal oxidase may contribute to the decrease in hepatic all-trans-retinol level and the increase in hepatic all-trans-RA caused by TCDD. Supplemental vitamin A might decelerate the effect of TCDD on retinal oxidase mRNA.
authors.affiliation: Molecular Biology Center, Medical College of Shantou University, 22 Xin Ling Road, Shantou 515041, People's Republic of China.
authors.forename: Yan-Mei
authors.initials: YM
authors.lastname: Yang
authors.forename: Dong-Yang
authors.initials: DY
authors.lastname: Huang
authors.forename: Ge-Fei
authors.initials: GF
authors.lastname: Liu
authors.forename: Jiu-Chang
authors.initials: JC
authors.lastname: Zhong
authors.forename: Kun
authors.initials: K
authors.lastname: Du
authors.forename: Yi-Fan
authors.initials: YF
authors.lastname: Li
authors.forename: Xu-Hong
authors.initials: XH
authors.lastname: Song
mesh_terms: D000217:Acyltransferases / Q000235:genetics; D000426:Alcohol Dehydrogenase; D042931:Aldehyde Oxidase; D000445:Aldehyde Oxidoreductases / Q000235:genetics; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D006706:Homeostasis; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010084:Oxidation-Reduction; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D014212:Tretinoin / Q000097:blood / Q000378:metabolism; D014801:Vitamin A / Q000097:blood / Q000378:metabolism*
chemical_list: D000072317:Polychlorinated Dibenzodioxins; D012333:RNA, Messenger; D014801:Vitamin A; D014212:Tretinoin; D000426:Alcohol Dehydrogenase; D000445:Aldehyde Oxidoreductases; D042931:Aldehyde Oxidase; C493760:Aox1 protein, mouse; D000217:Acyltransferases; C056942:lecithin-retinol acyltransferase