Abstract

The present chapter will discuss the potential of free-radical generation via xanthine oxidase during exercise based on the indirect evidence that exists of such an event. Somewhat paradoxical, free-radical generation via the xanthine oxidase reaction is paralleled by the formation of a free-radical scavenger. Uric acid, the second product in the xanthine oxidase reaction, has been found in vitro and, to some extent in vivo, to be an efficient scavenger of free radicals, including the highly reactive hydroxyl radical. Uric acid exists in high concentrations in plasma of most mammals including man and it has been suggested that the plasma uric acid concentration of different animals is in fact correlated to longevity. Recent studies demonstrate that uric acid may be an important free-radical scavenger in muscle during exercise. An overview will be given of the findings with regard to uric acid as a scavenger of radicals during various experimental conditions, including exercise. aus der Einleitung