The genotoxic potential of bases and nucleosides.

This study was conducted to determine if naturally occurring cell constituents could themselves cause mutation. All the bases and their corresponding nucleosides have been shown to produce chromosome damage in P338 mouse lymphoma and Chinese hamster ovary cells in culture. In addition thymidine has produced an increase in V79 cells resistant to 8-azaguanine and ouabain. Such damage probably arises as a result of imbalanced DNA-precursor pools. Thus mutagenic events may arise by mechanisms unrelated to direct alterations to DNA.