Detection and localization of CYP1A1/CYP1A2 in murine liver: electrophoresis, immunoblotting and immunocytochemistry.
Multiple forms of cytochrome P450 exist some of which are selectively inducible by exposure of the organism to a variety of foreign compounds. In this study, a monoclonal antibody specific for 3-methyl-cholanthrene-inducible cytochrome P450, Mab 1-7-1, was used to detect, localize and quantify CYP1A1/CYP1A2 in livers of C57BL/6 mice. Mab 1-7-1 recognized a faint band in the range between 45-66 Kd in Western immunoblots of liver microsomes from control mice, and a strong band in the same range, in liver microsomes from beta-naphthoflavone-treated mice. Microsome from control liver contained minimal levels of CYP1A1/CYP1A2; pretreatment with beta-naphthoflavone caused an increase in their expression. Immunoelectron microscopy was used to demonstrate the cellular localization and quantification of these isozymes in the liver. The immunolabeling procedure confirmed the endoplasmic reticulum as the primary site of CYP1A1/CYP1A2 induction in hepatocytes. This organelle showed the highest labeling density after treatment with beta-naphthoflavone. Increase in CYP1A1/CYP1A2 was 33.4-fold by morphometric analysis in induced hepatocytes in comparison to non-induced cells. In conclusion, CYP1A1/CYP1A2 is highly induced by beta-naphthoflavone in C57BL/6 mouse liver, and the cellular site of expression is the endoplasmic reticulum.
Oladapo
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Department of Anatomy, Queen's University, Kingston, Ontario, Canada.
Forkert
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D000818:Animals; D015153:Blotting, Western; D019363:Cytochrome P-450 CYP1A1 / Q000032:analysis* / Q000187:drug effects; D019388:Cytochrome P-450 CYP1A2 / Q000032:analysis* / Q000187:drug effects; D004586:Electrophoresis; D004721:Endoplasmic Reticulum / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007150:Immunohistochemistry; D008099:Liver / Q000737:chemistry* / Q000201:enzymology*; D008297:Male; D008748:Methylcholanthrene; D051379:Mice; D008810:Mice, Inbred C57BL; D019324:beta-Naphthoflavone / Q000494:pharmacology
D004791:Enzyme Inhibitors; D008748:Methylcholanthrene; D019324:beta-Naphthoflavone; D019363:Cytochrome P-450 CYP1A1; D019388:Cytochrome P-450 CYP1A2