Benzo[a]pyrene metabolism by hepatic and extrahepatic tissues in streptozotocin-diabetic rats

The metabolism of benzo[a]pyrene (BP) by microsomes from hepatic and extrahepatic tissues of female diabetic rats was investigated. Diabetes was produced by the administration of streptozotocin, 60 mg/kg iv, and BP metabolism was studied 7 or 10 days later. BP metabolism was increased in hepatic microsomes by 75% in diabetic animals. Cytochrome P-450 levels were similarly increased. BP mono-oxygenase activity was tripled in intestinal microsomes of diabetic rats, and returned to control values on insulin treatment. The BP mono-oxygenase activity in lung microsomes from diabetic rats decreased by 40%, and was increased to control levels after insulin treatment. No significant changes in BP metabolism were observed in the kidney and adrenal tissues of diabetic animals.