Indirect alkylation of CBA mouse liver DNA and RNA by hydrazine in vivo. A possible mechanism of action as a carcinogen.

Treatment of inbred CBA mice with hydrazine sulfate, a liver carcinogen, plus [14C]formate or L-[methyl-14C]-methionine as a source of "C1" units, produced [14C]7-methylguanine (7-MG) in liver DNA and RNA. This methylated guanine was identified by its chromatographic characteristics in three different systems: on Sephadex G10, on Dowex 50, and by paper co-chromatography with authentic 7-MG. Mice that received [14C]formate alone showed no 7-MG in their DNA or RNA. In addition, mice treated with L-[methyl-14C]methionine alone showed no 7-MG in their DNA. These results suggest that "indirect" alkylation of nucleic acids is a mechanism of cancer initiation by hydrazine.