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Journal of Biomolecular Screening Mar 2008Drug-metabolizing enzymes are an important battery of proteins that are involved in drug metabolism, xenobiotic detoxification, and drug-induced toxicity. Systematic,...
Drug-metabolizing enzymes are an important battery of proteins that are involved in drug metabolism, xenobiotic detoxification, and drug-induced toxicity. Systematic, efficient, and simultaneous evaluation of drug-metabolizing gene expression in response to chemicals has a wide variety of implications in drug development, disease prevention, and personalized medicine and nutrition. In the current study, the authors have systematically and simultaneously evaluated the hepatic expression profile of drug-metabolizing enzymes in cultured human hepatocytes exposed to the xenobiotics rifampicin, omeprazole, and 3-methylcholanthrene (3-MC) using the Drug Metabolism RT(2)Profiler PCR Arrays. This new high-throughput tool allowed the authors to evaluate the expression of genes coding for 84 drug-metabolizing enzymes (including phase 1 and phase 2 drug-metabolizing enzymes and transporters) simultaneously, in a 96-well format using a small amount of experimental materials. To validate the quality of the Drug Metabolism RT(2)Profiler PCR Arrays, the PCR Array was compared with the well-documented platform TaqMan assay, and a high concordance was shown between these 2 methods, indicating the high reliability of the Drug Metabolism RT(2)Profiler PCR Arrays. In addition, increasing or decreasing the expression of drug-metabolizing enzymes by these 3 compounds was observed, and underlying mechanisms are discussed.
Topics: Brain; Cells, Cultured; Gene Expression Profiling; Gene Expression Regulation; Hepatocytes; Humans; Inactivation, Metabolic; Methylcholanthrene; Omeprazole; Polymerase Chain Reaction; Principal Component Analysis; RNA; Rifampin
PubMed: 18270363
DOI: 10.1177/1087057108315513 -
European Journal of Biochemistry Mar 1985The Ah receptor protein, important in the mechanism of induction of aryl hydrocarbon hydroxylase activity, has been identified and partially characterized in hepatic...
The Ah receptor protein, important in the mechanism of induction of aryl hydrocarbon hydroxylase activity, has been identified and partially characterized in hepatic cytosolic preparations from rat, BALB/c mouse, gerbil, hamster, rabbit, ferret and guinea-pig by means of sucrose density centrifugation analysis and hydroxyapatite binding assays. Using 2,3,7,8-tetrachloro[3H]dibenzo-p-dioxin (TCDD) as the ligand, total specific binding capacities ranged over 74-691 fmol [3H]TCDD/mg cytosolic protein and apparent dissociation constants ranged over 0.30-7.8 nM. There was no quantitative correlation between the concentration of cytosolic Ah receptors and the 3-methylcholanthrene-mediated induction of aryl hydrocarbon hydroxylase activity in the species studied. Competitive binding studies with a series of monohydroxylated benzo[a]pyrene derivatives suggested the importance of electronic character in their ability to bind to the Ah receptor and to compete with TCDD for specific binding sites on the receptor.
Topics: Animals; Aryl Hydrocarbon Hydroxylases; Binding, Competitive; Centrifugation, Density Gradient; Chemical Phenomena; Chemistry; Cricetinae; Cytosol; Enzyme Induction; Ferrets; Gerbillinae; Guinea Pigs; Male; Methylcholanthrene; Mice; Mice, Inbred BALB C; Microsomes, Liver; Polychlorinated Dibenzodioxins; Rabbits; Rats; Rats, Inbred Strains; Receptors, Aryl Hydrocarbon; Receptors, Drug; Species Specificity
PubMed: 2982617
DOI: 10.1111/j.1432-1033.1985.tb08767.x -
Fukuoka Igaku Zasshi = Hukuoka Acta... May 2005The in vitro metabolism of 2,3',4,4',5-pentachlorobiphenyl (pentaCB) (CB118) was studied using liver microsomes of guinea pigs and the effect of cytochrome P450... (Comparative Study)
Comparative Study
The in vitro metabolism of 2,3',4,4',5-pentachlorobiphenyl (pentaCB) (CB118) was studied using liver microsomes of guinea pigs and the effect of cytochrome P450 inducers, phenobarbital (PB) and 3-methylcholanthrene (MC) on CB118 metabolism was also compared. After 30 min-incubation at 37 degrees C with liver microsomes of guinea pigs, CB118 was hydroxylated to two metabolites (M(-1) and M(-2)) with retention times of 15.84 min and 20.01 min in GC/ECD, respectively. GC/MS showed that the methylated derivative of a major metabolite M(-2) had the molecular weight of 354 and an intense fragment ion of [M(+)-50] which is a characteristic ion for PCBs possessing a methoxy-group at the 2 (2')- or the 6 (6')-position. By comparison of the mass fragmentation and the retention times in GC/MS with the synthetic authentic compounds, M(-2) was identified as 2-hydroxy-3,3',4,4',5-pentaCB (CB126). On the other hand, the methylated derivative of a minor metabolite M(-1) had the molecular weight of 320 and the similar fragment ion of [M(+)-50] to the methylated M(-2), assuming that M(-1) was a dechlorinated monohydroxy-tetrachlorobiphenyl (tetraCB) possessing hydroxy-group at the 2 (2')- or the 6 (6')-position. However, the precise structure of M-1 could not be determined because its retention time in GC was in disagreement with that of the candidate 6-hydroxy-3,3',4,4'-tetraCB. PB-treatment increased the formation of M(-1) and M(-2) to 2.2- and 6.8-fold of untreated animals, whereas MC-treatment increased only M(-2) to 2.6-fold of untreated ones. Addition of antiserum against a PB-inducible guinea pig cytochrome P450, CYP2B18, completely inhibited the formation of M(-2). These results suggest that CB118 is principally metabolized by CYP2B18 to 2-hydroxy-CB126 which is formed via a 2,3-epoxide intermediate and the subsequent NIH-shift of a chlorine at the 2-position to the 3-position in guinea pig liver.
Topics: Animals; Cytochrome P-450 Enzyme System; Guinea Pigs; In Vitro Techniques; Male; Methylcholanthrene; Microsomes, Liver; Phenobarbital; Polychlorinated Biphenyls
PubMed: 15997779
DOI: No ID Found -
Archives of Toxicology Aug 2017Epidemiologic studies suggest an increased risk of lung cancer with exposure to welding fumes, but controlled animal studies are needed to support this association....
Epidemiologic studies suggest an increased risk of lung cancer with exposure to welding fumes, but controlled animal studies are needed to support this association. Oropharyngeal aspiration of collected "aged" gas metal arc-stainless steel (GMA-SS) welding fume has been shown by our laboratory to promote lung tumor formation in vivo using a two-stage initiation-promotion model. Our objective in this study was to determine whether inhalation of freshly generated GMA-SS welding fume also acts as a lung tumor promoter in lung tumor-susceptible mice. Male A/J mice received intraperitoneal (IP) injections of corn oil or the chemical initiator 3-methylcholanthrene (MCA; 10 µg/g) and 1 week later were exposed by whole-body inhalation to air or GMA-SS welding aerosols for 4 h/d × 4 d/w × 9 w at a target concentration of 40 mg/m. Lung nodules were enumerated at 30 weeks post-initiation. GMA-SS fume significantly promoted lung tumor multiplicity in A/J mice initiated with MCA (16.11 ± 1.18) compared to MCA/air-exposed mice (7.93 ± 0.82). Histopathological analysis found that the increased number of lung nodules in the MCA/GMA-SS group were hyperplasias and adenomas, which was consistent with developing lung tumorigenesis. Metal deposition analysis in the lung revealed a lower deposited dose, approximately fivefold compared to our previous aspiration study, still elicited a significant lung tumorigenic response. In conclusion, this study demonstrates that inhaling GMA-SS welding fume promotes lung tumorigenesis in vivo which is consistent with the epidemiologic studies that show welders may be at an increased risk for lung cancer.
Topics: Administration, Inhalation; Air Pollutants, Occupational; Animals; Disease Models, Animal; Inhalation Exposure; Lung Neoplasms; Male; Methylcholanthrene; Mice; Mice, Inbred Strains; Occupational Diseases; Occupational Exposure; Stainless Steel; Welding
PubMed: 28054104
DOI: 10.1007/s00204-016-1909-2 -
The Journal of Investigative Dermatology Oct 1954
Topics: Aging; Animals; Methylcholanthrene; Mice; Mice, Hairless; Neoplasms, Experimental; Skin
PubMed: 13201816
DOI: 10.1038/jid.1954.106 -
The Journal of Biological Chemistry Nov 1983The aryl hydrocarbon hydroxylase inducers 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3-methylcholanthrene, and benzo(a)pyrene were all shown to bind in a saturable...
The aryl hydrocarbon hydroxylase inducers 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3-methylcholanthrene, and benzo(a)pyrene were all shown to bind in a saturable manner to a distinct component in cytosol from both rat and C57BL/6J mouse liver. This component was analyzed by gel permeation chromatography on Sephacryl S-300 and by sucrose density gradient centrifugation and was found to have a Stokes radius of 61 +/- 1.5 A and a sedimentation coefficient of 4.4 S under high salt conditions. Based on these parameters, which were identical for the rat and mouse receptor, a molecular weight of 111,000 was calculated. The same Stokes radius and sedimentation coefficient were observed regardless of the ligand used for labeling of the receptor protein [(3H]TCDD, 3-[3H]methylcholanthrene or [3H]benzo(a)pyrene). On the other hand, 3-[3H]methylcholanthrene and [3H]benzo(a)-pyrene exhibited much more nonspecific binding than [3H]TCDD, at least partially due to contaminating serum components, and it cannot be excluded that some previous findings on low molecular weight hepatic "receptors" for these polyaromatic hydrocarbons may actually be explained in this way. Clearly, use of thoroughly perfused livers would seem to be a prerequisite for investigations on specific binding of aryl hydrocarbon hydroxylase inducers to liver cytosol. The rat hepatic TCDD receptor was also shown to be retained on DEAE-Sepharose (eluted at 0.2-0.3 M NaCl), hydroxylapatite (eluted at 0.15-0.17 M phosphate), and heparin-Sepharose (eluted at 0.3-0.4 M NaCl). In conclusion, the TCDD receptor showed similar physicochemical and chromatographic characteristics to those previously reported for the androgen and glucocorticoid receptors. However, ligand competition experiments indicated that the TCDD receptor is not identical to any steroid receptor. In line with this, monoclonal anti-glucocorticoid receptor-IgG antibodies did not react with the TCDD receptor.
Topics: Animals; Benzo(a)pyrene; Benzopyrenes; Carcinogens; Chromatography, Gel; Cytosol; Kinetics; Liver; Male; Methylcholanthrene; Mice; Mice, Inbred C57BL; Molecular Weight; Polychlorinated Dibenzodioxins; Polycyclic Compounds; Rats; Rats, Inbred Strains; Receptors, Aryl Hydrocarbon; Receptors, Drug
PubMed: 6315701
DOI: No ID Found -
The Tohoku Journal of Experimental... Mar 1985An animal model for the emphysematous bullae in the rabbit lung induced by methylcholanthrene and carrageenan was reported. In early stages (by 2 months) the cystic...
An animal model for the emphysematous bullae in the rabbit lung induced by methylcholanthrene and carrageenan was reported. In early stages (by 2 months) the cystic lesions associated with extensive pneumonia. In later stages the inflammation subsided and only the cystic lesions remained, resulting in typical, large emphysematous bullae.
Topics: Animals; Carrageenan; Cysts; Drug Synergism; Lung; Lung Diseases; Male; Methylcholanthrene; Necrosis; Pneumonia; Pulmonary Emphysema; Rabbits
PubMed: 4002221
DOI: 10.1620/tjem.145.341 -
Nucleic Acids Research Mar 1986A cDNA clone for the Ya subunit of glutathione transferase from rat liver was constructed in E. coli. The clone hybridized to Ya and Yc subunit messenger RNAs. On the... (Comparative Study)
Comparative Study
A cDNA clone for the Ya subunit of glutathione transferase from rat liver was constructed in E. coli. The clone hybridized to Ya and Yc subunit messenger RNAs. On the basis of experiments involving cell-free translation and hybridization to the cloned probe, it was shown that prototype inducers of cytochrome P-450 such as phenobarbitone and 3-methylcholanthrene as well as inhibitors such as CoCl2 and 3-amino-1,2,4-triazole enhanced the glutathione transferase (Ya+Yc) messenger RNA contents in rat liver. A comparative study with the induction of cytochrome P-450 (b+e) by phenobarbitone revealed that the drug manifested a striking increase in the nuclear pre-messenger RNAs for the cytochrome at 12 hr, but did not significantly affect the same in the case of glutathione transferase (Ya+Yc). 3-Amino-1,2,4-triazole and CoCl2 blocked the phenobarbitone mediated increase in cytochrome P-450 (b+e) nuclear pre-messenger RNAs. These compounds did not significantly affect the glutathione transferase (Ya+Yc) nuclear pre-messenger RNA levels. The polysomal, poly (A)- containing messenger RNAs for cytochrome P-450 (b+e) increased by 12-15 fold after phenobarbitone administration, reached a maximum around 16 hr and then decreased sharply. In comparison, the increase in the case a glutathione transferase (Ya+Yc) messenger RNAs was sluggish and steady and a value of 3-4 fold was reached around 24 hr. Run-off transcription rates for cytochrome P-450 (b+e) increased by nearly 15 fold in 4 hr after phenobarbitone administration, whereas the increase for glutathione transferase (Ya+Yc) was only 2.0 fold. At 12 hr after the drug administration, the glutathione transferase (Ya+Yc) transcription rates were near normal. Administration of 3-amino-1,2,4-triazole and CoCl2 blocked the phenobarbitone-mediated increase in the transcription of cytochrome P-450 (b+e) messenger RNAs. These compounds at best had only marginal effects on the transcription of glutathione transferase (Ya+Yc) messenger RNAs. The half-life of cytochrome P-450 (b+e) messenger RNA was estimated to be 3-4 hr, whereas that for glutathione transferase (Ya+Yc) was found to be 8-9 hr. Administration of phenobarbitone enhanced the half-life of glutathione transferase (Ya+Yc) messenger RNA by nearly two fold. It is suggested that while transcription activation may play a primary role in the induction of cytochrome P-450 (b+e), the induction of glutathione transferase (Ya+Yc) may essentially involve stabilization of the messenger RNAs.
Topics: Amitrole; Animals; Cell Nucleus; Cobalt; Cytochrome P-450 Enzyme System; DNA; Gene Expression Regulation; Glutathione Transferase; Liver; Male; Methylcholanthrene; Phenobarbital; Protein Biosynthesis; Rats; Time Factors; Transcription, Genetic
PubMed: 3754327
DOI: 10.1093/nar/14.6.2497 -
The Biochemical Journal Aug 1978The fatty acid compositions of the lipids and the lipid peroxide concentrations and rates of lipid peroxidation were determined in suspensions of liver endoplasmic...
The fatty acid compositions of the lipids and the lipid peroxide concentrations and rates of lipid peroxidation were determined in suspensions of liver endoplasmic reticulum isolated from rats fed on synthetic diets in which the fatty acid composition had been varied but the remaining constituents (protein, carbohydrate, vitamins and minerals) kept constant. Stock diet and synthetic diets containing no fat, 10% corn oil, herring oil, coconut oil or lard were used. The fatty acid composition of the liver endoplasmic reticulum lipid was markedly dependent on the fatty acid composition of the dietary lipid. Feeding a herring-oil diet caused incorporation of 8.7% eicosapentaenoic acid (C(20:5)) and 17% docosahexaenoic acid (C(22:6)), but only 5.1% linoleic acid (C(18:2)) and 6.4% arachidonic acid (C(20:4)), feeding a corn-oil diet caused incorporation of 25.1% C(18:2), 17.8% C(20:4) and 2.5% C(22:6) fatty acids, and feeding a lard diet caused incorporation of 10.3% C(18:2), 13.5% C(20:4) and 4.3% C(22:6) fatty acids into the liver endoplasmic-reticulum lipids. Phenobarbitone injection (100mg/kg) decreased the incorporation of C(20:4) and C(22:6) fatty acids into the liver endoplasmic reticulum of rats fed on a lard, corn-oil or herring-oil diet. Microsomal lipid peroxide concentrations and rates of peroxidation in the presence of ascorbate depended on the nature and quantity of the polyunsaturated fatty acids in the diet. The lipid peroxide content was 1.82+/-0.30nmol of malonaldehyde/mg of protein and the rate of peroxidation was 0.60+/-0.08nmol of malonaldehyde/min per mg of protein after feeding a fat-free diet, and the values were increased to 20.80nmol of malonaldehyde/mg of protein and 3.73nmol of malonaldehyde/min per mg of protein after feeding a 10% herring-oil diet in which polyunsaturated fatty acids formed 24% of the total fatty acids. Addition of alpha-tocopherol to the diets (120mg/kg of diet) caused a very large decrease in the lipid peroxide concentration and rate of lipid peroxidation in the endoplasmic reticulum, but addition of the synthetic anti-oxidant 2,6-di-t-butyl-4-methylphenol to the diet (100mg/kg of diet) was ineffective. Treatment of the animals with phenobarbitone (1mg/ml of drinking water) caused a sharp fall in the rate of lipid peroxidation. It is concluded that the polyunsaturated fatty acid composition of the diet regulates the fatty acid composition of the liver endoplasmic reticulum, and this in turn is an important factor controlling the rate and extent of lipid peroxidation in vitro and possibly in vivo.
Topics: Animals; Antioxidants; Dietary Fats; Endoplasmic Reticulum; Fatty Acids; Lipid Metabolism; Liver; Male; Methylcholanthrene; Microsomes, Liver; Peroxides; Phenobarbital; Rats
PubMed: 708411
DOI: 10.1042/bj1740585 -
Chemico-biological Interactions Apr 1981All of the 13 possible polychlorinated biphenyl (PCB) isomers and congeners substituted at both para positions, at least two meta positions (but not necessarily on the...
All of the 13 possible polychlorinated biphenyl (PCB) isomers and congeners substituted at both para positions, at least two meta positions (but not necessarily on the same ring) and at two ortho positions have been synthesized and tested as rat hepatic microsomal enzyme inducers. The effects of these compounds were evaluated by measuring microsomal benzo-[a]pyrene (B[a]P) hydroxylase, 4-chlorobiphenyl (4-CBP) hydroxylase, 4-dimethylaminoantipyrine (DMAP) N-demethylase and NADPH-cytochrome c reductase activities, the cytochrome b5 content and the relative peak intensities and spectral shifts of the carbon monoxide(CO)- and ethylisocyanide(EIC)-difference spectra of ferrocytochrome P-450. The results were compared to the effects of administering phenobarbitone (PB), 3-methylcholanthrene (MC) and PB plus MC (coadministered). At dose levels of 150 mumol . kg-1, all of the PCB congeners, except 2,3',4,4',5',6-hexachlorobiphenyl, significantly enhanced hepatic microsomal cytochrome P-450 content, B[a] P hydroxylase and/or DMAP N-demethylase activities compared to the control (corn oil-treated) animals. Only 5 of these compounds, namely 2,3,4,4',5,6-hexa-, 2,2',3,3',4,4'-hexa-, 2,2',3',4,4',5-hexa-, 2,3,3',4,4',6-hexa-and 2,2',3,3',4,4',5-heptachlorobiphenyl, enhanced microsomal B[a]P hydroxylase, 4-CBP hydroxylase, NADPH-cytochrome c reductase and DMAP N-demethylase activities in a manner consistent with a mixed pattern of induction. The results suggest that PCB isomers and congeners substituted at both para positions, at least two meta positions, at two ortho positions and containing a 2,3-4-trichloro substitution pattern on one ring are mixed-type inducers; in addition the effects of 2,3,4,4',5,6-hexachlorobiphenyl were also consistent with a mixed pattern of induction.
Topics: Animals; Enzyme Induction; Male; Methylcholanthrene; Microsomes, Liver; Phenobarbital; Polychlorinated Biphenyls; Rats; Structure-Activity Relationship
PubMed: 6781768
DOI: 10.1016/0009-2797(81)90059-4