Influence of one bout of vigorous exercise on ascorbic acid in plasma and oxidative damage to DNA in blood cells and muscle in untrained rats

We investigated the influence of a single exhaustive bout of downhill runni ng on oxidative damage to DNA and changes of antioxidant vitamin concentrat ions in rats. Plasma vitamin E levels were unchanged up to 48 hr postexerci se. However, plasma ascorbic acid (AA) levels increased after the exercise, then decreased thereafter. This increase corresponded to a marked decrease in AA concentration in the adrenal glands. The activity of hepatic l-gulon o-gamma -lactone oxidase, which catalyzes AA synthesis, was unaltered after the exercise. The weight of the adrenal glands was significantly increased 24 hr postexercise. These results indicate that the change in the plasma A A concentration after vigorous exercise was due mainly to the release of AA from the adrenal glands. The plasma creatine phosphokinase (CPK) activity and white blood cell (WBC) count increased 3 to 6 hr postexercise. Over thi s same period, a marker of oxidative DNA damage, 8-hydroxydeoxyguanosine in DNA, increased in the WBC, but not in the foreleg muscle. Lipid peroxide a nd vitamin E levels were also unchanged in the foreleg muscle. There was a positive correlation between CPK activity in the plasma and DNA damage in t he WBC, suggesting that the DNA damage in the WBC was closely related with muscle damage due to exercise. (J. Nutr. Biochem. 11:401-407, 2000) (C) Els evier Science Inc. 2000. All rights reserved.