Tritiated carcinogenic 4-nitroquinoline 1-oxide was injected subcutaneously into groin of mice and quantitative analyses of this carcinogen and its metabolites (4-hydroxyaminoquinoline 1-oxide, 4-aminoquinoline 1-oxide, 4-aminoquinoline, 4-hydroxyquinoline 1-oxide, and 4-hydroxyaminoquinoline) in blood, lung, and liver were carried out in addition to the site of injection, following the reverse dilution method for analysis of labeled compounds. The metabolites were accumulated in the lung to a higher extent than in liver or spleen at the earlier stage of metabolism. Quantitative analyses of metabolites revealed that (i) the concentration tration of 4-nitroquinoline 1-oxidew as extremelyl ower than that of 4-hydroxyaminoquinoline 1-oxide in any organs and blood except at the site of injection, (ii) liver contained non-carcinogenic metabolites almost exclusively, including only traces of carcinogenic 4-nitro- and 4-hydroxyamino-quinoline 1-oxide, and (iii) 4-hydroxyaminoquinoline was found in metabolites in addition to other four metabolites previously reported.
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