Barrows L R
Mutat Res. 1986 Jan;173(1):73-9. doi: 10.1016/0165-7992(86)90014-x.
Treatment of rats with radioactive methionine and nonradioactive dimethylnitrosamine resulted in the formation of radioactive 7-methylguanine in rat-liver DNA. By comparing the specific activity of administered [14C-Me]-dimethylnitrosamine to the specific activity of isolated 7-methylguanine it was determined that following 20 mg/kg dimethylnitrosamine DNA methylation via the 1-carbon pool may account for up to 30% of the total 7-methylguanine formed.