Abstract
Summary A comparative study of the carcinogenicity of 4-nitroquinoline 1-oxide and 4-hydroxyaminoquinoline 1-oxide was carried out using C3H/HeN, C57BL/6JN and non-inbred albino strains of mice. Ten subcutaneous injections of these carcinogens at a same and relatively low dose (0.1 mg per time) were made once a week into the same site on the back of the mice. More sarcomas developed in the C3H mice than in the other 2 strains, whereas leukemia was mostly observed in non-inbred albino mice. The C57 BL mice showed the least tumor incidence. The tumor yields obtained within the observation period of 32 weeks clearly showed that 4-hydroxyaminoquinoline 1-oxide was more active than 4-nitroquinoline 1-oxide. The result of this study would support the hypothesis that 4-nitroquinoline 1-oxide acts through its reduced form.