title: Activities of several phase I and phase II xenobiotic biotransformation enzymes in cultured hepatocytes from male and female rats.
abstract: Hepatocytes were isolated from adult male and female rats and maintained in monolayer culture for up to 24 hr. The degree of preservation of representative phase I and phase II xenobiotic biotransformation enzymes was studied in these cells immediately after isolation, after attachment in culture, and after 24 hr in culture. Regarding phase I pathways, hepatocytes during 24 hr lost 50% of cytochrome P-450, but maintained high mixed function oxidase activities; 75% of aryl hydrocarbon hydroxylase and 65% of benzphetamine demethylase activities were preserved in hepatocytes from males, whereas in hepatocytes from females 70 and 50% of these activities, respectively, were maintained. Of phase II pathways, glutathione transferase activity after 24 hr, tested toward 1,2-dichloro-4-nitrobenzene as substrate, was diminished in male hepatocytes to 20% of the initial liver activity and in female cells, to 35%, whereas the activity tested toward 1-chloro-2,4-dinitrobenzene as substrate was stable. UDP-glucuronosyltransferase activities, tested toward p-nitrophenol and phenolphthalein as substrates, were slightly increased during 24 hr of culture of hepatocytes to levels higher than in liver before perfusion. The level of UDP-glucuronic acid, the endogenous substrate for the enzyme, was reduced after isolation to only 6% of the initial liver value, and then increased during culture to a level approximately 60% of normal. Thus, the changes in xenobiotic biotransformation enzymes and associated constituents in cultured hepatocytes were not uniform, although biotransformation capability remained reasonably intact.
mesh_terms: D000818:Animals; D001711:Biotransformation; D002478:Cells, Cultured; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004137:Dinitrochlorobenzene / Q000378:metabolism; D005260:Female; D014453:Glucuronosyltransferase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000378:metabolism; D009578:Nitrobenzenes / Q000378:metabolism; D009596:Nitrophenols / Q000378:metabolism; D010084:Oxidation-Reduction; D010089:Oxidoreductases, N-Demethylating / Q000378:metabolism; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D020113:Phenolphthalein; D010635:Phenolphthaleins / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D004137:Dinitrochlorobenzene; D009578:Nitrobenzenes; D009596:Nitrophenols; D004364:Pharmaceutical Preparations; D010635:Phenolphthaleins; D020113:Phenolphthalein; D003577:Cytochrome P-450 Enzyme System; C028328:1,2-dichloro-4-nitrobenzene; D006899:Mixed Function Oxygenases; C019781:benzphetamine N-demethylase; D010089:Oxidoreductases, N-Demethylating; D014453:Glucuronosyltransferase; D005982:Glutathione Transferase; C024836:4-nitrophenol