Cell cycle-specific mutagenesis at the hypoxanthine phosphoribosyltransferase locus in adult rat liver epithelial cells.

The cell cycle specificity of chemical mutagenesis was studied by use of two cell synchronization techniques, one a nontoxic technique involving serum deprivation and the other a double thymidine block, to obtain rat liver epithelial cells in different phases of the cell cycle to be exposed to chemical mutagens. For both methyl methanesulfonate and N-methyl-N'-nitro-N-nitrosoguanidine, there was a cell cycle specificity of chemical mutagenesis, with the most sensitive phase being the period of DNA synthesis.