Increased activity of pyruvate kinase in plasma of vitamin E-deficient rats.

The effect of dietary vitamin E on activities of pyruvate kinase and lactate dehydrogenase was studied in tissues of rats. The activity of pyruvate kinase in plasma of 1-month-old male rats fed a vitamin E-deficient diet for 4 months increased 8.5-fold over that of 45 ppm vitamin E-supplemented animals. Relative to the supplemented group, the enzyme activity increased 23% (P less than 0.001) in red blood cells, was unchanged in liver and lung, and decreased 20% (P less than 0.001) in muscle of vitamin E-deficient rats. The activity of lactate dehydrogenase was not significantly altered by dietary vitamin E in all tissues measured. Similar results were obtained when 2-month-old rats were fed the respective diets for 3 months. The results suggest that vitamine E deficiency in rats may cause muscular damage and release of pyruvate kinase into blood circulation.