Cytochrome P 450 content and the ability of liver microsomes from patients undergoing abdominal surgery to alter the mutagenicity of a primary and a secondary carcinogen

The capacity of microsomes isolated from patients undergoing abdominal surgery to alter the mutagenicity of a primary and a secondary carcinogen was investigated and related to the cytochrome P 450 content of the liver. Such microsomes activated the mutagenic effect on bacteria of the secondary carcinogen dimethylnitrosamine and inactivated that of the primary carcinogen N methyl N nitro N nitrosoguanidine. The differential ability of microsomes to alter mutagenicity varied in parallel with cytochrome P 450 content. This suggests great variability in the capacity of patients examined to metabolize carcinogens by their microsomes.