Respiration, activity of oleate oxidation and composition of the total fatty acids of rat liver were investigated in 3'-Me-DAB feeding. 1. Oxidative phosphorylation of rat liver mitochondria decreased temporarily at relatively earlier stages (about 2 to 3 weeks) in 3'-Me-DAB feeding. 2. The activity of oleate oxidation of rat liver mitochondria decreased rapidly to about one third of that in control groups after the start of 3'-Me-DAB feeding. 3. In the composition of the total fatty acids of rat liver, the proportion of oleic acid increased in 3'-Me-DAB groups. 4. Unknown octadecamonoenoic acid was observed in liver mitochondria of rat fed on 3'-Me-DAB. 5. Proportions of oleic and palmitoleic acids in liver tumors and mitochondria of liver tumors induced by 3'-Me-DAB feeding increased remarkably in contrast with decrease in those of palmitic and eicosapolyenoic acids. 6. A possibility was discussed about how higher level of oleate in the liver cells in azo dye feeding may be concerned with the tumor induction.</p
