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Background: In case of overdose of paracetamol the ability of hepatic biotransformation is saturated and accumulation of toxic metabolite – NAPQI takes place. Main CYP isoforms considered to be responsible for bioactivation of APAP and promoting the same liver intoxication are CYP2E1, CYP1A2, CYP3A4 and in animals 2B1/2 isoforms additionally. Purpose of this work was examination of paracetamol influence and/or trichloroethylene on the composition of hepatic cytochrome P450 isoforms. Materials and method: Tests were carried out on rats which were treated with trichloroethylene, paracetamol and/or N-acetylcysteine. In the microsomal fraction content of three isoforms of cytochrome P450 i.e. CYP2E1, CYP2B1/2 and CYP1A2 were determined. Results: Paracetamol slightly stimulated CYP2B1/2 lowering simultaneously level of CYP1A2. Trichloroethylene stimulated CYP2B1/2. N-acetylcysteine stimulated all tested P450 isoforms. N-acetylcysteine given together with examinated xenobiotics induced studied P450 isoforms. Conclusions: N-acetylcysteine demonstrated a protective effect on studied CYP isoforms especially when was given upon termination of xenobiotics exposure

Background: Feature of modern existing hazards both environmental and occupational is cumulative exposure often leading to unexpected response of the organism resulting, among other things, in interactions with cytochrome P450 system involved in biotransformation of trichloroethylene and paracetamol. Hepatotoxity of paracetamol is closely connected with hepatic glutathione level. „In therapy of acute paracetamol poisoning application of N-acetylcysteine as a factor, which protects GSH level in cells, is recommended.” Materials and method: Tests were performed on rats which were treated with trichloroethylene, paracetamol and/or N-acetylcysteine. In rat liver total level of glutathione was determined i.e. reduced and oxidized form. Results: Paracetamol just after completion of the exposure affected the glutathione level. Trichloroethylene throughout the period of observation stimulated growth of glutathione level in liver. N-acetylcysteine didn’t have any influence on the level of investigated tripeptyde. Conclusions: N-acetylcysteine removes negative effect of paracetamol especially when it’s applied with 2-hour delay. After exposure for trichloethylene immediate application of N-acetylcysteine caused noticeable lowering of glutathione level. Cumulative exposure for three xenobiotics had positive influence for glutathione level in rat liver.

Background: There is a number of factors which potentially affect occurrence of toxic change in liver after overdosing of paracetamol. Hepatic metabolism of trichloroethylene has primary impact on hepatotoxic effect of this solvent. This means that the combined exposure to these xenobiotics can be particularly harmful for human. The influence of N-acetylcysteine (NAC) as a protective factor after paracetamol intoxication was studies. Materials and method: Tests were carried out on rats which were treated with trichloroethylene, paracetamol and/or N-acetylcysteine. In the hepatic microsomal fraction activity of the components of cytochrome P450- dependent monooxygenases was determined Results: Paracetamol slightly stimulated cytochrome P450 having no effect on reductase activity cooperating with it. Cytochrome b5 and its reductase were inhibited by this compound. Trichloroethylene was the inhibitor of compounds of II microsomal electron transport chain. N-acetylcysteine inhibited activity of reductase of NADH-cytochrome b5. Conclusions: Tested doses of the xenobiotics influenced on II microsomal electron transport chain. Protective influence of N-acetylcysteine was better if this compound was applied 2 hours after exposure on xenobiotics