Toxicity of Intraperitoneal Injections of 7,12-Dimethylbenz[a]anthracene in Inbred Mice1

The sensitivity of A/HeJ, AKR/J, C3H/HeJ, C57BL/6J, C58/J, and DBA/2J male mice to single i.p. injections of 7,12dimethylbenz[a]anthracene (DMBA) was investigated. The drug was administered in a single dose of 0.75 to 3 mg per mouse and animals were sacrificed 5-20 days after injection. The AKR mice were least affected by DMBA. Acute ]>eritoneal inflamma tion accompanied by accumulation of an exÃodatewas pronounced in the C57BL/6, A/He, C58, C3H/He mice and only slight in DBA/2 and AKR mice. Depression of the lymphocyte count in the peripheral blood and decrease of the weight of spleen and thymus were also more pronounced in strains with increased mortality rates and severe jieritoneal inflammation. Toxicity remained the same whether sesame oil, dimethyl sulfoxide, or hexadecane were the solvents, but decreased when DMBA was suspended in physiologic saline containing Tween 80. Male and female AKR and C57BL/6 mice responded the same to treatment.