Journal Article

Leucine accelerates blood ethanol oxidation by enhancing the activity of ethanol metabolic enzymes in the livers of SHRSP rats

Komai, Michio, Furukawa, Yuji, Murakami, Hitoshi, Ito, Michiko

2012

Overview

Chronic ethanol consumption induces liver diseases, such as alcoholic hepatitis and cirrhosis. The enhancement of alcohol oxidation is important in the prevention of these liver diseases. Chronic supplementation with branched chain amino acids (BCAAs) prevents liver cirrhosis. Therefore, BCAAs may be associated with enhanced ethanol oxidation. To evaluate this hypothesis, we investigated the effect of the administration of individual BCAAs on ethanol oxidation and changes in alcohol-metabolizing enzyme activities following acute alcohol intake in rats. Blood ethanol concentrations and the activities of alcohol-metabolizing enzymes, such as alcohol dehydrogenase (ADH) and low and high Km aldehyde dehydrogenase (ALDH), were measured in the liver following acute ethanol administration in rats; the ethanol was administered 30 min after the treatment with amino acids [such as leucine (Leu), isoleucine (Ile), valine (Val) or alanine (Ala)]. Leu significantly decreased the blood ethanol concentration 1 h after ethanol administration compared to the water-treated control (C) [C 0.46 ± 0.09, Leu 0.18 ± 0.04, Ile 0.27 ± 0.09, Val 0.46 ± 0.1, Ala 0.43 ± 0.06, mean ± SEM (g/l), P < 0.05]. In addition, leucine significantly stimulated ADH activity 30 min after ethanol intake [C 0.042 ± 0.014, Leu 0.090 ± 0.016, Ile 0.042 ± 0.008, Val 0.022 ± 0.010, Ala 0.070 ± 0.016, mean ± SEM (unit/mg protein), P < 0.05] and low Km ALDH activity 15 min after ethanol intake [C 0.51 ± 0.63, Leu 3.72 ± 0.66, Ile 1.26 ± 0.89, Val: ND, Ala 1.86 ± 1.57, mean ± SEM (unit/mg protein), P < 0.05]. However, leucine and its metabolite α-keto-isocaproic acid did not enhance ethanol clearance in isolated rat hepatocytes. These results indicate that leucine accelerates ethanol oxidation by indirectly enhancing ADH and low Km ALDH activities in the liver.

• Publisher: Springer-Verlag,Springer Science and Business Media LLC,Springer Vienna,Springer Nature B.V
• Subject: Alanine / Alcohol / alcohol abuse / Alcohol Dehydrogenase / Alcohol Dehydrogenase - metabolism / alcohol drinking / alcoholic hepatitis / Aldehyde Dehydrogenase / Aldehyde Dehydrogenase - metabolism / Aldehydes / Amino acids / Analytical Chemistry / Animals / Biochemical Engineering / Biochemistry / Biomedical and Life Sciences / Blood / Blood levels / branched chain amino acids / Chain branching / Cirrhosis / Dehydrogenases / Enzymatic activity / enzyme activity / Enzymes / Ethanol / Ethanol - administration & dosage / Ethanol - blood / Ethanol - metabolism / Ethyl alcohol / Hepatitis / Hepatocytes / Isoleucine / Leucine / Leucine - administration & dosage / Leucine - metabolism / Leucine - pharmacology / Life Sciences / Liver / Liver - drug effects / Liver - enzymology / Liver - metabolism / Liver cirrhosis / Liver diseases / Metabolites / Neurobiology / Original Article / Oxidation / Oxidation resistance / Oxidation-Reduction / Proteins / Proteomics / Rats / Rats, Inbred SHR / Rats, Sprague-Dawley / Rats, Wistar / Scanning electron microscopy / Time Factors / Valine