Abstract
In previous paper, it was shown that the oral supplementation of 75μg per day of riboflavin on rat cause an increase of liver xanthine oxidase and an accumulation of riboflavin, FAD and FMN in liver. In this paper, the further experiment with riboflavin-deficient rat was done to elucidate the mechanism of the increase of xanthine oxidase activity. A marked increase of liver xanthine oxidase activity was observed when 1mg of inosine and 15 or 3Oμg of riboflavin are supplemented, whereas a significant relation between enzyme activity and accumulation of riboflavin in liver could not demonstrated. Therefore, the authors intend to conclude that the increase of xanthine oxidase activity is due to an induced reaction of inosine.
