Objective. This article reviews the biochemistry and function of xanthine dehydrogenase
(XDH) and xanthine oxidase (XO) as well as their role in hypoxia-reoxygenation injury.
Possible benefits of XO blockade are discussed. Methodology. The available literature was
reviewed. Results. It is evident that relatively high activities of XO are restricted to a few
organs in man. Because positive effects of XO blockade with allopurinol have been reported
even in organs containing relatively low activities of XO, two other possible favorable actions …