This research will investigate the relative contribution of various metabolic routes of ethanol metabolism in control and ethanol-fed deermice. A recently established strain that is genetically deficient for alcohol dehydrogenase (ADH) along with ADH+ controls will be used as an animal model to determine the role of ADH in ethanol metabolism under naive and ethanol-fed conditions. Groups of ADH+ and ADH- mice will be pair-fed control and ethanol-containing liquid diets for 4-5 weeks. Activities of several microsomal components will be measured in the 4 groups of animals. The molecular species of cytochrome P-450 will be determined by HPLC and the capacity of particular groups to support ethanol oxidation will be assessed in reconstituted system. Measurements will be made of in vivo rates of ethanol metabolism at varying concentrations in control and ethanol-fed ADH+ and ADH- mice. Aminotriazole will be used to inhibt catalase in certain experiments. Isolated hepatocytes from similarly treated animals will be tested for their ability to oxidize ethanol at varying concentrations. These experiments are designed to determine the relative contribution of ADH, catalase, and MEOS pathways to ethanol oxidation before and after chronic ethanol consumption. Some of the pathological consequences of ethanol oxidation by ADH are hypothesized to be due to redox changes in the cell. Development of fatty liver will be assessed by light microscopy and measurements of total lipids and triglycerides. Acetaldehyde levels in ADH+ and ADH- animals fed control or ethanol containing diets will be assessed after acute ethanol administration. Other pathological consequences of chronic ethanol consumption in ADH+ and ADH- mice, such as mitochondrial impairment and collagen accumulation, will be determined by biochemical measurements. Through the judicious exploitation of a unique experimental model, namely the feeding of alcohol-containing liquid diets to the ADH- deermouse, the planned experiments may clarify the longstanding debate concerning the relative role of various ethanol metabolizing pathways in the metabolism of ethanol, its adaptive increase after chronic consuption and its contribution to the development of alcoholic fatty liver.
