Phenobarbital-induced increase of the hexose 6-phosphate dehydrogenase activity

The intracellular and intramicrosomal distributions of hexose 6-phosphate dehydrogenase were examined in the livers of normal and starved rats before and after phenobarbital treatment. The results have revealed that the administration of phenobarbital (75 mg/kg body weight, 4 days) causes a significant increase of the hexose 6-phosphate dehydrogenase activity only in smooth-surfaced, but not in rough-surfaced endoplasmic reticulum, with concomitant increases of the activities of NADPH-cytochrome c reductase and aminopyrine demethylase. Starvation prior to the phenobarbital treatment enhanced the effect of phenobarbital on the microsomal enzymes.