Effects of methyl methacrylate on non-protein thiols and drug metabolizing enzymes in rat liver and kidneys.
Male Wistar rats received methyl methacrylate monomer (MMA) i.p. in olive oil 1.0 g/kg body weight on 3 successive days. The weight of the livers and kidneys, and the body weights did not differ from their controls. On the fifth day after treatment, hepatic NADPH-cytochrome c reductase, 7-ethoxycoumarin 0-deethylase and the 2,5-diphenyloxazole hydroxylase exhibited maximal decreases in activity (25%, 58%, 36%, respectively) without any coincident effect on the total amount of cytochrome P-450 hemoprotein itself. One week later these activities had returned to control levels. The enzymatic changes in the kidneys were smaller in magnitude, and they were also reversed sooner. A single i.p. dose of MMA (2 g/kg body weight) caused elevation of serum alanine aminotransferase activity. A tenfold increase of the excretion rate of urinary thioethers was also discovered. The hepatic reduced glutathione (GSH) was depleted in 3 h to 20% and the GSSG to half of the value in controls. In kidneys, the GSH was decreased to 48% in 3 h before an apparent phase of overrecovery. At the end of the 24 h observation period, cytochrome P-450 concentrations were somewhat decreased in the liver. The GSH contents showed dose and time-dependent reversible decreases in isolated hepatocytes when incubated for 2 h in a medium containing MMA at the nominal concentrations of 0, 2, 5, or 10 mM. None of the treatments affected either the content of cytochrome P-450 or the viability of the liver cells.
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004851:Epoxide Hydrolases / Q000378:metabolism; D014453:Glucuronosyltransferase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D020366:Methylmethacrylate; D008768:Methylmethacrylates / Q000494:pharmacology*; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013438:Sulfhydryl Compounds / Q000378:metabolism*
D008768:Methylmethacrylates; D013438:Sulfhydryl Compounds; D020366:Methylmethacrylate; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D014453:Glucuronosyltransferase; D004851:Epoxide Hydrolases; D005978:Glutathione