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Clinical Science (2003) 104, (287–294) (Printed in Great Britain)
Chronic a-tocopherol supplementation in rats does not ameliorate either chronic or acute alcohol-induced changes in muscle protein metabolism
Michael KOLL*, Julie A. BEESO†, Frank J. KELLY†, Ulrich A. SIMANOWSKI‡, Helmut K. SEITZ§, Timothy J. PETERS
 and Victor R. PREEDY**Department of Nutrition and Dietetics, King's College London, Franklin-Wilkins-Building, Stamford Street, London SE1 9NN, U.K., †School of Health and Life Sciences, King's College London, Franklin-Wilkins-Building, Stamford Street, London SE1 9NN, U.K., ‡Department of Gastroenterology and Oncology, Werner Forsmann Krankenhaus, Teaching Hospital, Freie Universitaet Berlin, Eberswalde, Germany, §Department of Medicine, Salem Medical Centre, Heidelberg, Germany, and
Department of Clinical Biochemistry, King's College London, Medical School, Bessemer Road, London SE5 9PJ, U.K.Key words: alcohol, protein synthesis, skeletal muscle, a-tocopherol. Abbreviations: ATC, a-tocopherol; i.p., intraperitoneally; kRNA, activity per unit RNA; kS, fractional rate of protein synthesis; LSD, least significant difference. Correspondence: Dr Michael Koll, present address: MBC 03, Department of Biological and Medical Research, King Faisal Specialist Hospital and Research Centre, P.O. Box 3354, Riyadh 11211, Saudi Arabia (e-mail mkoll@kfshrc.edu.sa). 
Chronic alcohol muscle disease is characterized by reduced skeletal muscle mass precipitated by acute reduction in protein synthesis. The pathogenic mechanisms remain obscure, but several lines of evidence suggest that increased oxidative stress occurs in muscle in response to alcohol and this may be associated with impaired a-tocopherol status. Potentially, this implies a therapeutic role for a-tocopherol, especially as we have shown that supplemental a-tocopherol may increase the rate of protein synthesis in normal rats [Reilly, Patel, Peters and Preedy (2000) J. Nutr. 130, 3045–3049]. We investigated the therapeutic effect of a-tocopherol on plantaris muscle protein synthesis in rats treated either acutely, chronically or chronically+acutely with ethanol. Protein synthesis rates were measured with a flooding dose of L-[4-3H]phenylalanine. Protein, RNA and DNA contents were determined by standard laboratory methods. Ethanol caused defined metabolic changes in muscle, including decreased protein, RNA and DNA contents in chronically treated rats. In acute or chronic+acute studies, ethanol suppressed fractional rates of protein synthesis. a-Tocopherol supplementation did not ameliorate the effects of either acute, chronic or chronic+acute alcohol on plantaris muscle protein content or rates of protein synthesis. In control animals (not treated with alcohol), a-tocopherol supplementation decreased muscle protein content owing to increases in protein turnover (both synthesis and degradation). a-Tocopherol supplementation is not protective against the deleterious effects of alcohol on protein metabolism in skeletal muscle.
Received 4 November 2002; accepted 6 December 2002
The Biochemical Society and the Medical Research Society © 2003 |
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