Factors influencing xanthine oxidase activity in rat skin.

One of the earliest studies reporting the presence of xanthine oxidase in rat skin was made by Barry et al. (1). Westerfeld and Richer-t (2), in a study of the distribution of this enzyme in the tissues of the white rat, confirmed this finding and reported that activity in the skin accounted for approximately 20% of the total xanthine oxidase of the rat. These authors did not study the enzyme in detail in this tissue because of the di&ulty in preparing skin homogenates. Evidence has been accumulated which would seem to indicate that a purine-catabolizing system exists in rat skin (3, 4). The present work represents a study of xanthine oxidase in skin, designed to provide more detailed information concerning its significance in skin metabolism. The specific purposes of this investigation were: (a) to attempt to demonstrate changes in skin xanthine oxidase activity with the age of the rat, and (b) to compare xanthine oxidase in skin and liver.