AIM:To study the effect of both acute and chronic alcohol exposure on heme oxygenases(HOs) in the brain,liver and duodenum.METHODS:Wild-type C57BL/6 mice,heterozygous Sod2 knockout mice,which exhibit attenuated manganese superoxide dismutase activity,and liver-specific ARNT knockout mice were used to investigate the role of alcohol-induced oxidative stress and hypoxia.For acute alcohol exposure,ethanol was administered in the drinking water for 1 wk.Mice were pair-fed with regular or ethanol-containing Lieber De Carli liquid diets for 4 wk for chronic alcohol studies.HO expression was analyzed by real-time quantitative polymerase chain reaction and Western blotting.RESULTS:Chronic alcohol exposure downregulated HO-1 expression in the brain but upregulated it in the duodenum of wild-type mice.It did not alter liver HO-1 expression,nor HO-2 expression in the brain,liver or duodenum.In contrast,acute alcohol exposure decreased both liver HO-1 and HO-2 expression,and HO-2 expression in the duodenum of wild-type mice.The decrease in liver HO-1 expression was abolished in ARNT+/-mice.Sod2+/-mice with acute alcohol exposure did not exhibit any changes in liver HO-1 and HO-2 expression or in brain HO-2 expression.However,alcohol inhibited brain HO-1 and duodenal HO-2 but increased duodenal HO-1 expression in Sod2+/-mice.Collectively,these findings indicate that acute and chronic alcohol exposure regulates HO expression in a tissue-specific manner.Chronic alcohol exposure alters brain and duodenal,but not liver HO expression.However,acute alcohol exposure inhibits liver HO-1 and HO-2,and also duodenal HO-2 expression.CONCLUSION:The inhibition of liver HO expression by acute alcohol-induced hypoxia may play a role in the early phases of alcoholic liver disease progression. AIM: To study the effect of both acute and chronic alcohol exposure on heme oxygenases (HOs) in the brain, liver and duodenum. METHODS: Wild-type C57BL / 6 mice, heterozygous Sod2 knockout mice, which exhibit attenuated manganese superoxide dismutase activity, and liver-specific ARNT knockout mice were used to investigate the role of alcohol-induced oxidative stress and hypoxia. For acute alcohol exposure, ethanol was administered in the drinking water for 1 wk. Micron were pair-fed with regular or ethanol-containing Lieber De Carli liquid diets for 4 wk for chronic alcohol studies. HO expression was analyzed by real-time quantitative polymerase chain reaction and Western blotting .RESULTS: Chronic alcohol exposure downregulated HO-1 expression in the brain but upregulated it in the duodenum of wild- type mice. It did not alter liver HO-1 expression, nor HO-2 expression in the brain, liver or duodenum. contrast, acute alcohol exposure decreased both HO HO and HO-2 expression, and HO- the duodenum of wild-type mice. The decrease in liver HO-1 expression was abolished in ARNT +/- mice.Sod2 +/- mice with acute alcohol exposure did not exhibit any changes in liver HO-1 and HO-2 expression or in brain HO -2 expression. However, alcohol inhibited brain HO-1 and duodenal HO-2 but increased duodenal HO-1 expression in Sod2 +/- mice. Collectively, these findings indicate that acute and chronic alcohol exposure regulates HO expression in a tissue-specific manner . Chronic alcohol exposure alters brain and duodenal, but not liver HO expression. Despite acute alcohol exposure inhibits liver HO-1 and HO-2, and also duodenal HO-2 expression. CONCLUSION: The inhibition of liver HO expression by acute alcohol- induced hypoxia may play a role in the early phases of alcoholic liver disease progression.