METHYL ORANGE & ITS METAB, N,N-DIMETHYL-P-PHENYLENEDIAMINE WERE MUTAGENIC TO SALMONELLA TYPHIMURIUM WHEN TESTED IN PRESENCE OF LIVER HOMOGENATE. SULFANILIC ACID ANOTHER METABOLITE WAS NOT MUTAGENIC.
When various dyes and indicators were fed to partially hepatectomized male rats as supplements in basal diet for 10 days after surgery, liver regeneration was stimulated by 1-phenylazo-2-naphthol and by 1-(p-phenylazophenylazo)-2-naphthol, as such or with methyl substituents on the phenyl rings, and also by methyl orange. The efficacy of the azonaphthiols stemmed from the activity of the metabolic intermediate, 1-amino-2-naphthol, which was tested in rats at a level of 0.20% (as the hydrochloride). The presence of a nitro group pr two methoxy groups of the phenyl ring of 1-phenylazo-2-naphthol or of sulfonic acid groups on either of the azonaphthol series led to cmpd that were ineffective. The stimulants generally elicited liver enlargement when fed to intact rats for the same interval. In contrast to p-dimethylaminoazobenzenesulfonate (methyl orange) ... was stimulatory. Sulfanilic acid, a prominent metabolite of several azo dyes, proved inactive in partially hepatectomized males at a level of 0.20%.
Clastogenic activity was evaluated in 3 cultures of RL1 rat liver cells per dose, exposed for 22 hours to 4-dimethylaminoazobenzene-4-sulphonic acid, sodium salt at concentrations of 0, 12.5, 25.0, or 50.0 ug/ml of culture medium. Concentrations were chosen to be approximately 1/4, 1/2, and 1x the GI50 (concentration at which 50% growth inhibition is achieved). Both positive (methyl-methanesulfonate) and solvent (dimethylsulfoxide) controls were used. No metabolic activation system was used. Cell division was arrested, and at least 380 metaphases from each test concentration were examined. The test substance did not induce a significant frequency of chromatid or chromosome aberrations. The proportions of cells showing chromatid aberrations were 0.7% for the negative control, 0% at both 12.5 and 25.0 ug/ml, and 0.3% at 50.0 ug/ml. The proportions showing chromosomal aberrations were 0.1% for the negative control, 0.3% at 25.0 ug/ml, and 0% at the other concentrations. Although the positive control showed 3.3% of cells with chromatid aberrations, no chromosome aberrations were induced.
KINETIC ANALYSIS OF BILIARY EXCRETION OF IV DOSE OF [(3)H]METHYL ORANGE & PRODUCTS OF DEMETHYLATION (MONO- & DI-) SHOWED THAT SUCCESSIVE REMOVAL OF METHYL GROUP RESULTED IN MUCH FASTER BILIARY EXCRETION OF CMPD.
BILIARY EXCRETION OF IV ADMIN METHYL ORANGE & METABOLITES, 4'-SULFO-4-METHYLAMINOAZOBENZENE & 4'-SULFO-4-AMINOAZOBENZENE, BY RATS WAS USED TO ILLUSTRATE A ONE-COMPARTMENT PHARMACOKINETIC MODEL IN WHICH A DRUG UNDERWENT 2 SUCCESSIVE METABOLIC REACTIONS.