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Effects of 2,3,7,8‐tetrachlorodibenzo‐ p ‐dioxin on vitamin A metabolism in mice
Author(s) -
Yang YanMei,
Huang DongYang,
Liu GeFei,
Zhong JiuChang,
Du Kun,
Li YiFan,
Song XuHong
Publication year - 2005
Publication title -
journal of biochemical and molecular toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.526
H-Index - 58
eISSN - 1099-0461
pISSN - 1095-6670
DOI - 10.1002/jbt.20097
Subject(s) - endocrinology , medicine , retinol , retinal , vitamin , retinoic acid , chemistry , oxidase test , metabolism , body weight , enzyme , biology , biochemistry , gene
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 μg TCDD/kg body weight, with or without continuous administration of 2500 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 μg TCDD/kg body weight, with or without supplemental 2000 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. © 2005 Wiley Periodicals, Inc. J Biochem Mol Toxicol 19:327–335, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/jbt.20097