The goals of this proposal is to delineate the role of acetaldehyde and aldehydic products of lipid peroxidation and their influence on Kupffer cell activity in alcoholic liver disease. Experiments are designed to analyze Kupffer cells from rats chronically ingesting ethanol to measure biochemical and molecular alterations that lead to Kupffer cell activation. The ethanol metabolizing pathways of alcohol dehydrogenase and aldehyde dehydrogenase will be assessed, as well as the metabolic capacity to detoxify ethanol and its metabolites, malondialdehyde, and 4-hydroxynonenal. Methods for detecting the oxidative status of Kupffer cells will be employed through analyses of antioxidant homeostasis and possible covalent binding of aldehydes to cellular proteins. The final experiments will assess Kupffer cell activation by determining inflammatory and fibrogenic cytokine production. These experiments will determine not only cytokine production, but also study the transcription factors that regulate the production of these cytokines. The studies outlined in this proposal are designed to elicit the connection between acetaldehyde and endproducts of lipid peroxidation and the alterations in Kupffer cell activity underlying the pathogenesis of alcoholic liver disease.