Immunochemically detected nuclear envelope-associated cytochrome P-450 component(s) in rat hepatocyte culture lines.
The presence and location of cytochrome P-450 in Donryu rat hepatocyte culture lines, Ac2F cells and 3 other cell lines were assessed by indirect immunofluorescence examination using anti-cytochrome P-450 monoclonal antibodies. Ac2F cells and other hepatocyte cell lines were selectively stained at their nuclear envelope, but not the cytoplasm, with a monoclonal antibody selective to a high-spin form of cytochrome P-448 (P-448H), although this monoclonal antibody stained primary cultured normal rat hepatocytes at both cellular components and did not stain hepatoma cells of 2 transplantation lines. The results of unscheduled DNA synthesis assay with Ac2F cells using several carcinogenic aromatic amines (4-aminoazobenzene derivatives and amino acid pyrolysis products) suggested that this nuclear envelope-associated cytochrome P-450 activates a restricted portion of these aromatic amines, i.e., a tryptophan pyrolysis component and a glutamic acid pyrolysis component. These results indicate that rat hepatocyte culture lines lack (or contain a reduced amount of) the cytoplasmic cytochrome P-450 but maintain a characteristic type of cytochrome P-450, probably a kind of cytochrome P-448H in their nuclear envelope, and this may be involved in oxidative metabolism of a restricted portion of aromatic amines.
D000818:Animals; D000911:Antibodies, Monoclonal; D002460:Cell Line; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis*; D004260:DNA Repair; D005455:Fluorescent Antibody Technique; D066298:In Vitro Techniques; D008099:Liver / Q000201:enzymology*; D009685:Nuclear Envelope / Q000201:enzymology; D051381:Rats
D000911:Antibodies, Monoclonal; D003577:Cytochrome P-450 Enzyme System