Induction of aryl hydrocarbon hydroxylase by 3-methylcholanthrene in liver,lung and kidney of gonadectomized and sham-operated wistar rats

Detailed dose-response curves have been obtained for the induction of aryl hydrocarbon hydroxylase (AHH) m liver, lung and kidney by intraperitoneally administered 3-methylcholanthrene (3-MC) in Wistar rats. The effects of gonadectomy also were studied. Lung was the tissue most sensitive to induction, followed by liver, and then kidney in all cases. Although liver exhibited the greatest overall activity, the per cent increase over control AHH levels was much higher in the two extrahepatic tissues. Gonadectomy did not affect either control or induced AHH activity in any of the three organs in the female, or in the male lung. However, castration of the males decreased control liver enzyme levels and increased these levels in kidney. The AHH levels reached after maximal 3-MC induction were the same in castrated and sham-operated male rat livers. A different pattern was seen in male kidney enzyme levels where significantly increased maximal induction was observed in castrated animals.