Putative role of antioxidant enzymes and glyoxalases in carcinogenesis.

The effects various drugs exert on antioxidant enzyme and glyoxalase activity in rat livers were studied. All drugs tested provoked a marked reduction in glutathione peroxidase and a small drop in both glyoxalase I and II activity. It is hypothesized that the substances tested support tumour development by neutralizing organic peroxides, thereby favouring the oxidation of carcinogens and, as a consequence, the formation of metabolites that trigger neoplastic transformation. The reduction in glyoxalase activity is probably attributable to the enhanced cell proliferation induced by the treatment.