title: Antioxidants inhibit the effect of vitamin C on oxygen radical-induced sister-chromatid exchanges.
abstract: The mechanism of vitamin C-induced sister-chromatid exchanges in cultured mammalian cells was studied. Chinese hamster ovary cells, when exposed to an enzymatic oxygen radical-generating system (xanthine oxidase plus hypoxanthine), develop increased numbers of sister-chromatid exchanges. Inclusion of ascorbate (greater than or equal to 0.1 mM) in these incubations resulted in an augmentation of this effect. Superoxide dismutase (100 microliter/ml) and catalase (220 microliter/ml) caused a significant reduction in the number of sister-chromatid exchanges induced by xanthine oxidase, hypoxanthine and vitamin C. Their heat-inactivated counterparts had no effect. These results confirm that vitamin C (greater than or equal to 0.1 mM) potentiates the genetic toxicity of oxygen radicals and that this effect is mediated by toxic oxygen intermediates.
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000037:antagonists & inhibitors*; D002374:Catalase / Q000378:metabolism; D002478:Cells, Cultured; D006224:Cricetinae; D005609:Free Radicals; D010100:Oxygen / Q000037:antagonists & inhibitors*; D012854:Sister Chromatid Exchange / Q000187:drug effects*; D013482:Superoxide Dismutase / Q000378:metabolism; D014969:Xanthine Oxidase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005609:Free Radicals; D002374:Catalase; D013482:Superoxide Dismutase; D014969:Xanthine Oxidase; D001205:Ascorbic Acid; D010100:Oxygen