Influence of nicotine on DNA metabolism

We investigated the influence of nicotine and its metabolites on semiconservative DNA synthesis, DNA repair processes, and the rejoining of DNA strand breaks. Using a combined treatment with nicotine and gamma irradiation and counting the number of sister chromatid exchanges, we evaluated the action of nicotine on the whole DNA repair process, especially examining the possibility that DNA is damaged by the action of nicotine. All tests were performed on HeLa cells and verified with human lung fibroblasts. Liver microsomes of aroclor-treated rats were used as the metabolizing agent. Our findings showed that nicotine and its metabolites at concentrations below 1 mmol/l are not toxic in the cell lines used and within this subtoxic range they have no effect on DNA metabolism. Neither was DNA repair obstructed after gamma irradiation nor did the number of sister chromatid exchanges increase.