Alkylated purines in the DNA of various rat tissues after administration of 1,2-dimethylhydrazine.

[1,2-3H] Dimethylhydrazine (1,2-DMH) (300 mg/kg; 4 mCi/kg) was injected s.c. to BD-VI rats and the degree of DNA alkylation was measured in various tissues 3 h after the administration. The O6-methylguanine/7-methylguanine ratio was approx. 4 times higher in the colon's DNA (0.0565), the principal target organ of this carcinogen, than in the liver's DNA (0.0136). These findings are briefly discussed in relation to the organ specificity of this carcinogen.