ANALYSIS OF BILIARY AND URINARY METABOLITES OF 3'-METHYL-4-(DIMETHYLAMINO)AZOBENZENE IN RATS

  • 1 January 1978
    • journal article
    • research article
    • Vol. 69  (6) , 757-762
Abstract
Metabolites of 3''-methyl-4-(dimethylamino)azobenzene (3''-Me-DAB) in the rat bile and urine were investigated by the use of a tracer technique. 3H-3''-Me-DAB in cottonseed oil was administered orally by a stomach tube. The dye metabolites in the bile and urine collected for 24 h after administration were hydrolyzed with .beta.-glucuronidase/arylsulfatase. The hydrolyzed metabolites were then extracted with chloroform or separated by chromatography on Amberlite XAD-2 using methanol as a solvent. The metabolites in the chloroform or methanol eluates were identified by the reverse isotope dilution analysis, before or after separation by TLC. The N-demethylated, aryl hydroxylated and their azo-reduced products were detected in the bile in addition to the products oxidized at the ring methyl group as the new metabolites. The metabolites retaining the azo-linkage were scarcely detected in urine; 3-aminobenzoic acid, 3-amino-6-hydroxytoluene, and their N-acetylated products were major metabolites in urine. The metabolism of 3''-Me-DAB in the rat apparently involves oxidation of the ring methyl group. Significance of the ring methyl group in the carcinogenic action of aminoazo dyes is discussed.