Effect of monensin on liver glutathione, glutathione S-transferase and monooxygenases in rats.

Monensin administered ip to male rats at a dosage of 2.5 mg/kg/d for 3 consecutive days did not change the liver levels of glutathione, but depressed significantly the amount of cytochrome P-450 and the activities of aniline hydroxylase and a cytosolic CDNB-specific glutathione S-transferase. There was a marked decrease in the aminopyrine N-demethylase activity and a significant increase in the pentobarbital sleeping time in rats treated with monensin. In contrast, no change in these parameters was found 2 h after a single ip dose (7.5 mg/kg) of monensin. The results suggest that monensin-induced inhibition of the liver cytosolic glutathione S-transferase and microsomal monooxygenases is non-specific.