Abstract
Acrylamide (AA) is an industrial chemical that has been extensively investigated for central nervous system (CNS), reproductive, and genetic toxicity. However, AA effects on the liver, a major organ of drug metabolism, have not been adequately explored. In addition, the role of mitochondria in AA-mediated toxicity is still unclear. Changes in expression levels of genes associated with hepatic mitochondrial function of male transgenic Big Blue (BB) mice administered 500 mg/L AA or an equimolar concentration (600 mg/L) of its reactive metabolite glycidamide (GA) in drinking water for 3 and 4 wk, respectively, were examined. Transcriptional profiling of 542 mitochondria-related genes indicated a significant downregulation of genes associated with the 3-beta-hydroxysteroid dehydrogenase family in AA- and GA-treated mice, suggesting a possible role of both chemicals in altering hepatic steroid metabolism in BB mice. In addition, genes associated with lipid metabolism were altered by both treatments. Interestingly, only the parental compound (AA) significantly induced expression levels of genes associated with oxidative phosphorylation, in particular ATP synthase, which correlated with elevated ATP levels, indicating an increased energy demand in liver during AA exposure. Acrylamide-treated mice also showed significantly higher activity of glutathione S-transferase in association with decreased levels of reduced glutathione (GSH), which may imply an enhanced rate of conjugation of AA with GSH in liver. These results suggest different hepatic mechanisms of action of AA and GA and provide important insights into the involvement of mitochondria during their exposures.
Acknowledgments
The authors very much appreciate Jessie B. Collins, Office of Scientific Coordination, and Sharon Shelton, Division of Genetic and Molecular Biology, for their excellent technical assistance. Also, the authors thank Drs. Sherry M. Lewis and Nan Mei for their critical review of the article. This research was partly supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011-0015128). The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the FDA.