Influence of the Diet on the Metabolism of Acetaldehyde in Rats

Abstract The acetaldehyde dehydrogenases of rat liver, the hepatic output of acetaldehyde and the rate of ethanol elimination were studied in two groups of female Sprague-Dawley rats fed on two different commercial standard diets (diet 1 and diet 2). The activity of the mitochondrial low-K_m enzyme was 2–3 times lower in rats fed on diet 1 as compared to rats fed on diet 2, whereas only slight differences were found in the activities of the high-K_m enzymes in the mitochondrial, the microsomal and the cytosol fractions. No differences were observed between the two groups in the activities of alcohol dehydrogenase, glutamate dehydrogenase, glucose-6-phosphatase or malic enzyme. The rate of ethanol elimination was 15 % lower, and the acetaldehyde level in the blood was 2–4 times higher in rats fed on diet 1 as compared to rats fed on diet 2. When the diets were interchanged between the two groups, the activity of the low-K_m enzyme increased or decreased twofold within 12 hrs. Starvation increased the activity of the low-K_m enzyme in rats fed on diet 1, but had no effect on the activity in rats fed on diet 2. The results suggest that diet 1 contains an inhibitor of the low-K_m enzyme, and that dietary factors may be of importance in the regulation of the hepatic output of acetaldehyde during ethanol metabolism.