Effects of phenobarbital and 3-methylcolanthrene treatment on microsomes of Morris hepatoma 3924-A, tumour-bearing and normal rat liver.
Microsomal cytochromes and some oxidative activities were determined in normal rat liver, tumour-bearing rat liver and Morris hepatoma 3924-A. Except for a moderate lowering of cytochromes and enzymes in host livers, the relation between TPNH-cytochrome c reductase activity and cytochrome P-450 TPNH reduction, both increased by phenobarbital (PB) and decreased by 3-methylcolanthrene (3-MC) treatment, is noteworthy. In tumour cytochromes b5 and P-450 are absent and TPNH-cytochrome c reductase is unmeasurable and not induced by PB or 3-MC treatment. Aminopyrine demethylase activity, instead, is comparable with normal or host liver and it is modified by PB or 3-MC treatment in the same way, despite the microsomal enzymes pathway disorganization. Microsomal enzymatic defect selectivity in tumours may be due to a deranged microsome-linked growth control.
D000633:Aminopyrine N-Demethylase / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000648:ultrastructure; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D003580:Cytochromes / Q000378:metabolism; D003593:Cytoplasm / Q000648:ultrastructure; D008099:Liver / Q000201:enzymology / Q000648:ultrastructure*; D008114:Liver Neoplasms, Experimental / Q000201:enzymology / Q000648:ultrastructure*; D008748:Methylcholanthrene / Q000494:pharmacology*; D008862:Microsomes, Liver / Q000187:drug effects* / Q000201:enzymology / Q000648:ultrastructure; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D010634:Phenobarbital / Q000494:pharmacology*; D051381:Rats
D003580:Cytochromes; D008748:Methylcholanthrene; D003577:Cytochrome P-450 Enzyme System; D000633:Aminopyrine N-Demethylase; D009251:NADPH-Ferrihemoprotein Reductase; D010634:Phenobarbital