Ethanol and acetaldehyde metabolism in rat strains genetically selected for their ethanol preference

A study was made of ethanol and acetaldehyde metabolism in both sexes in rat strains genetically selected for their ethanol preference. The strains are denoted by ANA (Alko, Non-Alcohol), which prefers water to a 10% (v/v) ethanol solution, and AA (Alko, Alcohol), which prefers the ethanol solution. Peripheral blood and freeze-stopped livers were used for the in vivo studies. A once-through perfusion technique was applied so that in the same liver ethanol and acetaldehyde oxidation, the cytoplasmic redox state and oxygen consumption could be measured. In the female rats of the AA strain there was a higher rate of ethanol oxidation and oxygen consumption, compared with those of the ANA strain. A greater difference was found between the sexes, the female rats of both strains having a more rapid ethanol oxidation and oxygen consumption, compared with the respective males. The AA strain displayed a significantly lower level of acetaldehyde during ethanol oxidation than did the ANA strain. On comparison of the liver acetaldehyde concentrations with the mitochondrial NADH/NAD⁺ ratio, calculated from the 3-hydroxybutyrate/acetoacetate ratio, strain correlations were observed in both sexes, the ANA strain, with higher acetaldehyde, having a lower 3-hydroxybutyrate/acetoacetate ratio than the AA strain, with lower acetaldehyde. The results are discussed in relation to the regulation of the ethanol and acetaldehyde metabolism. The biochemical basis for ethanol preference is briefly discussed.