title: Effect of dimethylnitrosamine concentration on its demethylation by liver microsomes from control and 3-methylcholanthrene pretreated rats, hamsters and guinea pigs.
abstract: The effect of dimethylnitrosamine concentration on its demethylation by liver microsomes from control and 3-methylcholanthrene pretreated (100 mg/kg body wt. 24 h before sacrifice) rats, hamsters and guinea pigs was investigated. At low substrate concentration (2 mM), liver microsomes from pretreated rats and hamsters showed 30-50% lower demethylation activity than their respective controls. No such difference was found in the guinea pig. At high substrate concentration (100 mM), all 3 pretreated species showed 50-100% higher enzyme activity than their respective controls. Enzyme activities among the 3 species showed the following order of activity: hamster greater than guinea pig greater than rat.
mesh_terms: D000818:Animals; D006224:Cricetinae; D004128:Dimethylnitrosamine / Q000378:metabolism*; D006168:Guinea Pigs; D008748:Methylcholanthrene / Q000494:pharmacology*; D008862:Microsomes, Liver / Q000378:metabolism*; D009602:Nitrosamines / Q000378:metabolism*; D051381:Rats; D013045:Species Specificity
chemical_list: D009602:Nitrosamines; D008748:Methylcholanthrene; D004128:Dimethylnitrosamine