title: Changes in rat liver microsomal cytochrome P-450 and enzymatic activities after the inhalation of n-hexane, xylene, methyl ethyl ketone and methylchloroform for four weeks.
abstract: Groups of Sprague-Dawley rats were exposed, by inhalation, to n-hexane (900 ppm, 3,240 mg/m3), xylene (600 ppm, 2,625 mg/m3), methyl ethyl ketone (800 ppm, 2,345 mg/m3) and methylchloroform (800 ppm, 4,345 mg/m3) for four weeks. Increased liver weights and liver to body weight ratios were observed for all the solvents except n-hexane. An increased in vitro formation of certain metabolites of all the investigated substrates was found only in the rats exposed to xylene. The in vitro microsomal metabolism of biphenyl, benzo(a)pyrene, 4-androstene-3,17-dione and 4 alpha-androstane-3 alpha, 17 beta-diol in combination with sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that n-hexane was without effect on rat liver microsomal cytochrome P-450 and that methyl ethyl ketone and methylchloroform depressed the formation of two metabolites of androstenedione but did not alter the concentration of cytochrome P-450 under the experimental conditions used. Xylene was shown to be a phenobarbital-like inducer of rat liver microsomal cytochrome P-450.
mesh_terms: D015113:Androstane-3,17-diol / Q000378:metabolism; D000735:Androstenedione / Q000378:metabolism; D000818:Animals; D002074:Butanones / Q000633:toxicity; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D006586:Hexanes / Q000633:toxicity; D006843:Hydrocarbons, Chlorinated / Q000633:toxicity*; D066298:In Vitro Techniques; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D012997:Solvents / Q000633:toxicity*; D014240:Trichloroethanes / Q000633:toxicity*; D014992:Xylenes / Q000633:toxicity
chemical_list: D002074:Butanones; D006586:Hexanes; D006843:Hydrocarbons, Chlorinated; D012997:Solvents; D014240:Trichloroethanes; D014992:Xylenes; C024566:1,1,1-trichloroethane; D015113:Androstane-3,17-diol; C026385:n-hexane; D000735:Androstenedione; C005222:methylethyl ketone; D003577:Cytochrome P-450 Enzyme System