Toxicity profile of benzo[a]pyrene in the male LacZ transgenic mouse (MutaMouse) following oral administration for 5 consecutive days.

The toxicity profile of benzo[a]pyrene (BP) was examined in the MutaMouse. The transgenic mouse integrated with lambda gt10 lacZ vectors is used worldwide as an experimental animal in in vivo mutagenesis testing systems. There are few toxicity studies including carcinogenicity in the MutaMouse, and so far only a few carcinogenicity studies of BP accompanied with hematological and plasma biochemical examinations have been conducted even in generic mice.

Comparison between in vivo mutagenicity and carcinogenicity in multiple organs by benzo[a]pyrene in the lacZ transgenic mouse (Muta Mouse).

To evaluate whether the in vivo mutagenicity test system using the lacZ transgenic mice (Muta Mouse) may be applied to carcinogenesis studies, both the in vivo mutagenicity and carcinogenicity of benzo[a]pyrene (BP) was tested in mice under the same administration conditions. The eleven organs of the mice on the 14th day after the final oral administration of BP at a dose of 125 mg kg(-1) day(-1) or corn oil for 5 consecutive days were tested for in vivo mutation by the positive-selection method. The data show that the colon had the highest lacZ mutant frequency (37-fold increase over the spontaneous frequency), followed by the ileum > forestomach > bone marrow, spleen > glandular stomach > liver, lung > kidney and heart.