Malformations induced in cultured rat embryos by enzymically generated active oxygen species.

Day 9.5 rat embryos were exposed in culture to xanthine/xanthine oxidase generated active oxygen species. Growth and development were assessed after 46 hr of culture. The treatment induced abnormalities of the neural suture, the severity of which increased in a dose-related manner with the concentration of substrate or enzyme. Glutathione (10 mM) or catalase (50 micrograms/ml) either partially or completely abolished the effects of xanthine/xanthine oxidase, whereas the addition of superoxide dismutase (50 micrograms/ml) or desferrioxamine (1mM) did not reduce the number of malformed embryos. These findings suggest that hydrogen peroxide and/or hydroxyl radicals are responsible for the effects of xanthine and xanthine oxidase.