In vitro mutagenic activity of 5-(3,3-dimethyl-1-triazeno)-imidazole-4-carboxamide (DTIC) in eukaryotic and prokaryotic cells.

The in vitro mutagenic activity of 5-(3,3-dimethyl-1-triazeno)-imidazole-4-carboxamide (DTIC), has been studied in bacteria and Chinese hamster cells with and without metabolic activation by rat liver microsomes. DTIC was found to be highly mutagenic in the two systems. It is noteworthy that DTIC in the prokaryotic systems did not require metabolic activation to be effective. By comparing the mutagenic activity on bacteria of DTIC and of its monomethyl-and hydroxy-methyl-derivatives (MIC and HMIC), it is evident that MIC and HMIC display a pattern of mutagenicity different from DTIC. It suggests that neither MIC nor HMIC are the direct responsible metabolites for the mutagenic activity of DTIC in bacteria.