The biphasic change of cytosolic acetyl-CoA hydrolase in rat liver during 3'-methyl-4-dimethylaminoazobenzene hepatocarcinogenesis.

When Donryu male albino rats were given diet containing 0.06% 3'-methyl-4-dimethyl-aminoazobenzene (3'-Me-DAB) for 20 weeks, the activity of cytosolic acetyl-CoA hydrolase in their livers decreased to about one-third the initial level in week 2, returned to the control level in week 7, and then decreased again to about one-tenth of the control in week 20. These changes in enzyme activity were parallel with changes in the amount of enzyme protein determined by ELISA. In 3'-Me-DAB-resistant rats, however, the enzyme activity and enzyme protein remained within the normal range during administration of 3'-Me-DAB-containing diet for 20 weeks and no tumors were detectable macroscopically. Interestingly, the biphasic change in this enzyme activity was inversely associated with the well known change of gamma-glutamyltranspeptidase activity during azo-dye-induced hepatocarcinogenesis.

3′–methyl‐4‐dimethylaminoazo‐benzene

γ‐glutamyltranspeptidase (EC 2.3.2.2)2