[Induction of cytochromes P-4501A and 2B in various rat organs, subjected to hexachlorobenzene and aroclor 1254]. / Induktsiia tsitokhormov P-4501A i 2B v raznykh organakh krys, poluchavshikh geksakhlorbenzol i arokhlor 1254.

ABSTRACT

The activity and content of CYP1A1, CYP1A2, CYP2B1 and CYP2B in the liver, lung and kidney of Wistar rats treated with hexachlorobenzene (HCB), Aroclor 1254 (AR), methylcholanthrene (MC) and phenobarbital (PB) were studied. Administration of MC and AR caused an increase in the ethoxyresorufin (ER) and methoxyresorufin (MR)-O-dealkylase activities in all organs. The effect of HCB on lung and kidney monooxygenases was considerably lower. The penthoxyresorufin (PR)-O-dealkylase activity in extrahepatic organs was at the same level for all treatments used in this study. Western blot analysis using monoclonal antibodies against CYP1A and CYP2B also revealed a tissue-specific expression of these proteins during different inductions. Whereas in the liver during MC, AR and HCB inductions one revealed immunologically identical CYP1A1 and CYP1A2, in MC lung only CYP1A1 was observed. In the lung of AR and HCB microsomes both CYP1A1 and CYP1A2 were found. In the kidney after treatment with AR or HCB only CYP1A1 was induced. These findings suggest that inducers of mixed type cause coordinated synthesis of CYP1A1 and CYP1A2 in the lung unobserved during MC induction. After treatment of rats with PB both CYP2B1 and CYP2B2 were observed in the liver, while only the former was found in the lung and kidney. HCB treatment did not significantly affect the induction picture. In the liver and lung of AR-treated rats, besides CYP2B1 and CYP2B2, one more P-450 was revealed whose nature is under discussion now. The data obtained thus suggest that induction of different P-450s is not only tissue-specific but also depends on the inducer type.