Species difference among experimental rodents in the activity and induction of cytochrome P-450 isozymes for mutagenic activation of carcinogenic aromatic amines.

The expressions of hepatic microsomal cytochrome P-450 isozymes in male rats, mice, hamsters and guinea pigs were studied comparatively with or without an ip injection of a cytochrome P-450 inducer. The activity and quantity of microsomal cytochrome P-450 isozymes were determined respectively by a bacterial mutation assay with Salmonella typhimurium TA98 and immunochemical assays using monoclonal antibodies against rat cytochrome P-450 isozymes. 3-Methoxy-4-aminoazobenzene (3-MeO-AAB), 2-amino-3-methyl-9H-pyrido[2,3-b]indole acetate (MeA alpha C) and 3-methylcholanthrene were used as cytochrome P-450 inducers, and 7 carcinogenic aromatic amines including 3-MeO-AAB and MeA alpha C were used as substrates for the mutation assay. By means of these assays, we examined the species differences among rodents in the activity and induction rate of hepatic cytochrome P-450 isozymes responsible for the mutagenic activation of carcinogenic aromatic amines.

cytochrome P‐450

3‐methylcholanthrene

3 ‐methoxy‐4‐aminoazobenzene

3‐amino‐1‐methyl‐5H‐pyrido[4,3‐b]indole acetate

2‐amino‐6‐methyldipyrido[1,2‐a:3′,2′‐d]imidazole hydrochloride

2‐aminodipyrido[1,2‐a:3′,2′‐d]imidazole hydrochloride

2‐amino‐3‐methyl‐9H‐pyrido‐[2,3‐b]indole acetate

2‐amino‐3‐methylimidazo[4,3‐f]‐quinoline

2‐amino‐3,8‐dimethylimidazo[4,5‐f]quinoline