Induction of sister chromatid exchanges in Chinese hamster cells by the reducing agents bisulfite and ascorbic acid

Sister chromatid exchanges (SCEs) are induced in Chinese hamster cells by a 2--3-h exposure to ascorbic acid or bisulfite in the concentration range 10(-4)--10(-2) M. This activity of these 2 chemicals was intensified when cell cultures were exposed to each agent for longer time periods (24 h). The divalent metal cation, Cu2+, was effective in potentiating the ability of ascorbic acid to induce SCEs and toxicity, suggesting that the autooxidation of ascorbic acid was involved in this action. The ability of sodium bisulfite to induce SCEs was not affected by variation in the concentration of 5'-bromodeoxyuridine used as a labelling compound. This was interpreted as supporting the view that bisulfite, not a synergistic reaction between bisulfite and BrdU, was responsible for the elevated SCE levels.