title: Effects of 3-methylcholanthrene pretreatment on microsomal hydroxylation of 2-acetamidofluorene by various rat hepatomas.
abstract: 1. The effects of 3-methylcholanthrene pretreatment on both N- and ring hydroxylation of 2-acetamidofluorene by microsomal preparations from various well-differentiated and poorly differentiated hepatomas, primary tumours and their host livers and kidneys were studied. 2. Well-differentiated Morris hepatomas 5123C, 5123D, 5123CTC and 7800 and their host livers had low hydroxylating activity. Pretreatment with 3-methylcholanthrene caused a several-fold increase in both N- and ring hydroxylation in the host livers whereas in all tumours except 5123CTC it caused a many-fold increase only in ring hydroxylation. 5123CTC tumour in addition showed a fourfold increase in N-hydroxylating activity. 3. Hydroxylating activities of poorly differentiated Morris hepatoma 7288CTC and Novikoff hepatoma were low and they could not be altered by 3-methylcholanthrene pretreatment. 4. Primary hepatomas produced by administration of 4-dimethylamino-3'-methylazobenzene could be stimulated to some extent on 3-methylcholanthrene pretreatment; however, primary mammary tumour produced by administration of 3-methylcholanthrene was not responsive to 3-methycholanthrene pretreatment. 5. Like host livers, kidneys of tumour-bearing animals could also be stimulated to some extent by 3-methylcholanthrene pretreatment.
mesh_terms: D000818:Animals; D002273:Carcinogens / Q000378:metabolism*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D005260:Female; D005449:Fluorenes / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008113:Liver Neoplasms / Q000378:metabolism*; D008748:Methylcholanthrene / Q000494:pharmacology*; D008862:Microsomes, Liver / Q000187:drug effects*; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000378:metabolism; D051381:Rats
chemical_list: D002273:Carcinogens; D005449:Fluorenes; D008748:Methylcholanthrene