Effect of inducers on the hepatic microsomal mixed function oxidase system of female rats during food restriction

We have studied the effects of food restriction (FR), and FR followed by inducer treatments on hepatic drug metabolizing enzymes, microsomal electron transport components, NADPH dependent lipid peroxidation and cytosolic glutathione-S-transferase activities in rats. Phenobarbital (PB; 80 mg/kg, ip) or 3-methylcholanthrene (3-MC; 20 mg/kg, ip) was administered to Wistar female rats after a feeding period of 30 days. As a result of either PB or 3-MC treatment, microsomal protein content, cytochrome P-450 and cytochrome b5 levels increased significantly while cytochrome C reductase activity was significantly higher in an libitum-fed animals only. Aminopyrine N-demethylase (APND) and acetanilide hydroxylase (ACOH) activities were raised significantly in ad libitum fed as well as FR animals. NADPH dependent lipid peroxidation and cytosolic glutathione-S-transferase activity were also enhanced due to PB and 3-MC treatment; but the magnitude of increase was less in FR animals. The APND activity increased to a greater extent than ACOH activity in FR animals following PB treatment. We have previously shown that ACOH activity increased to a greater extent than APND activity following PB and 3-MC treatment in FR male rats. Hence, it is suggested that the response of FR female rats to inducers is similar to the ad libitum fed controls except for the lower magnitude of increase in the parameters studied. The response also differs from that of adult male rats to the inducers. (C) 1998 Lippincott Williams & Wilkins.