EFFECT OF 2(3)-TERT-BUTYL-4-HYDROXYANISOLE ADMINISTRATION ON THE ACTIVITIES OF SEVERAL HEPATIC MICROSOMAL AND CYTOPLASMIC ENZYMES IN MICE

Administration of 2(3)-tert-butyl-4-hydroxyanisole (BHA) (0.75%) caused a marked increase in the activities of several hepatic enzymes in CD-1 mice. This was associated with increased liver weights and total protein contents, especially of the microsomal and cytosol fractions. While the specific content of cytochrome P-450 was decreased slightly in microsomes, the specific content of cytochrome b5 and the specific activities of cytochrome c reductases (NADPH- or NADH-dependent) were increased (2-fold). In spite of a slight decrease in the specific activities of aminopyrine demethylase and of benzo(a)pyrene hydroxylase, both aniline hydroxylase and UDP-glucronyltransferase activities were increased (2.7- and 4.6-fold respectively). The specific activity of a microsomal membrane marker enzyme, glucose-6-phosphatase, was decreased slightly (-25 per cent). In the cytosol fraction, the specific activities of glucose-6-phosphate dehydrogenase and of UDP-glucose dehydrogenase were increased (3.8- and 6.1-fold respectively). Differences were noted in the time cources of increase and decrease in these enzyme activities after initiation and discontinuation of BHA treatment. © 1979.