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Fukuoka Igaku Zasshi = Hukuoka Acta... May 2003The in vivo metabolism of 2,3,3',4,4'-pentachlorobiphenyl (CB105) was studied in hamsters and the effect of cytochrome P450 inducers, phenobarbital (PB) and... (Comparative Study)
Comparative Study
The in vivo metabolism of 2,3,3',4,4'-pentachlorobiphenyl (CB105) was studied in hamsters and the effect of cytochrome P450 inducers, phenobarbital (PB) and 3-methylcholanthrene (MC) on its metabolism was compared to rats. After administration of CB105 intraperitoneally at a dose of 3 mg/body, four metabolites, named M-1, M-2, M-3 and M-4, were detected in 5 days-feces of all groups and the formation ratio of the metabolites M-1-M-4 was 1:39:84:0.2 in untreated hamsters and 1:19:6.7:0.7 in untreated rats. On the basis of the mass spectra of four synthetic authentic compounds and the retention times on DB-1 and MPS50 columns, M-1, M-2, M-3 and M-4 were identified as 4'-hydroxy-2,3,3',4,5'-PenCB, 5'-hydroxy-CB105, 5-hydroxy-CB105 and 4-hydroxy-2,3,3',4',5-PenCB, respectively. The pretreatment of PB and MC resulted in about 2-fold fecal excretion of four metabolites in hamsters and in about 3-fold in rats. Of four metabolites, only M-4 were detected in the serum at 5 days after CB105 administration and the concentration was 0.39 microgram/ml of hamster serum and 0.28 microgram/ml of rat serum. In hamsters, the concentration of M-4 was increased to 1.8-fold of untreated animals by PB treatment and 2.6-fold by MC treatment. On the other hand, the treatment of rats with PB and MC did not show such an increase of serum M-4. These results suggested that the hamster oxidized 2,3,4-trichloro-substituted benzene ring predominantly rather than 3',4'-dichloro-substituted benzene ring differently from the rat and that M-4 formed in hamster liver distributed to the blood and retained there to a considerable extent in comparison with that formed in rat liver.
Topics: Animals; Cricetinae; Cytochrome P-450 Enzyme System; Enzyme Induction; Male; Mesocricetus; Methylcholanthrene; Microsomes, Liver; Phenobarbital; Polychlorinated Biphenyls; Rats; Rats, Wistar; Species Specificity; Structure-Activity Relationship
PubMed: 12872719
DOI: No ID Found -
The American Journal of Pathology Dec 1976The experiments described in this paper have demonstrated that hepatocytes cultured on floating collagen membranes for periods of 10 days retain their ability to respond... (Review)
Review
The experiments described in this paper have demonstrated that hepatocytes cultured on floating collagen membranes for periods of 10 days retain their ability to respond to the inducers of drug-metabolizing enzymes, phenobarbital and methylcholanthrene, by increases in cytochromes of the cytochrome P-450 complex. Since the regulation of these cytochromes is the rate-controlling factor in the metabolism of drugs and carcinogens in hepatocytes, such experiments indicate that hepatocytes cultured on floating collagen membranes retain those functions of the liver cell responsible for the metabolism and "activation" of carcinogenic substances. The data support this hypothesis and further indicate that this system may have potential application both in the investigation of hepatocarcinogenesis by chemicals in vitro and as a screening system for the detection of substances truly carcinogenic for the mammalian organism.
Topics: Animals; Aryl Hydrocarbon Hydroxylases; Carcinogens; Cells, Cultured; Collagen; Cytochrome P-450 Enzyme System; DNA Repair; Drug Interactions; Enzyme Induction; Enzymes; Female; Hydrocortisone; Liver; Membranes; Methylcholanthrene; Microsomes, Liver; Phenobarbital; Pregnancy; Rats; Tyrosine Transaminase
PubMed: 11697
DOI: No ID Found -
The Journal of Biological Chemistry Feb 1987A P-450, designated P-450a, with high testosterone 7 alpha-hydroxylase activity was purified from rat liver microsomes. Specific polyclonal antibody against this P-450...
A P-450, designated P-450a, with high testosterone 7 alpha-hydroxylase activity was purified from rat liver microsomes. Specific polyclonal antibody against this P-450 was used to screen a lambda gt11 expression cDNA library and a 1687-base pair cDNA was isolated and sequenced. The deduced protein had 492 amino acids, a calculated Mr of 56,016, and it shared 51 and 45% amino acid similarities to P-450e and P-450f, respectively. Regions of similarity were distributed in distinct areas of high and low similarity along the P-450a primary sequence. P-450a cDNA was introduced into yeast cells using the expression vector pAAH5, and the resultant yeast microsomes contained both a protein of identical electrophoretic mobility to that of rat P-450a and testosterone 7 alpha-hydroxylase activity. These results confirm enzyme reconstitution data and antibody inhibition data that P-450a possesses testosterone 7 alpha-hydroxylase activity. The antibody and cDNA probes were used to examine the mechanism of regulation of P-450a by inducers and during development. P-450a and its mRNA were present at low level in newborn rats and increased to maximal level at 1 week of age in both males and females. At age 12 weeks, however, the P-450a level decreased in males but remained elevated in females. Concomitant with the decrease in P-450a in adult males was an increase in level of another immunologically related P-450. In adult male rats, P-450a was induced almost 5-fold by administration of 3-methylcholanthrene and this induction was the result of an increase in its mRNA. These results establish testosterone 7 alpha-hydroxylase as a member of the P-450e gene family that is developmentally regulated, sex-dependent, and markedly inducible by 3-methylcholanthrene.
Topics: Amino Acid Sequence; Animals; Aryl Hydrocarbon Hydroxylases; Base Sequence; Cloning, Molecular; Cytochrome P-450 Enzyme System; DNA; Electrophoresis, Polyacrylamide Gel; Enzyme Induction; Isoenzymes; Male; Methylcholanthrene; Microsomes, Liver; Rats; Rats, Inbred Strains; Steroid Hydroxylases
PubMed: 3818621
DOI: No ID Found -
Archives of Toxicology Feb 2018Daily exposure to low doses of 3-methylcholanthrene (3MC) during the pubertal period in rats disrupts both follicular growth and ovulation. Thus, to provide new insights...
Daily exposure to low doses of 3-methylcholanthrene (3MC) during the pubertal period in rats disrupts both follicular growth and ovulation. Thus, to provide new insights into the toxicity mechanism of 3MC in the ovary, here we investigated the effect of daily exposure to 3MC on selected ovarian genes, the role of the aryl hydrocarbon receptor (AhR) and the level of epigenetic remodeling of histone post-transcriptional modifications. Immature rats were daily injected with 3MC (0.1 or 1 mg/kg) and mRNA expression of genes involved in different ovarian processes were evaluated. Of the 29 genes studied, 18 were up-regulated, five were down-regulated and six were not altered. To assess whether AhR was involved in these changes, we used the chromatin immunoprecipitation assay. 3MC increased AhR binding to promoter regions of genes involved in Notch signaling (Hes1, Jag1), activation of primordial follicles (Cdk2), cell adhesion (Icam1), stress and tumor progression (Dnajb6), apoptosis (Bax, Caspase-9) and expression of growth and transcription factors (Igf2, Sp1). Studying the trimethylation and acetylation of histone 3 (H3K4me3 and H3K9Ac, respectively) of these genes, we found that 3MC increased H3K4me3 in Cyp1a1, Jag1, Dnajb6, Igf2, Notch2, Adamts1, Bax and Caspase-9, and H3K9Ac in Cyp1a1, Jag1, Cdk2, Dnajb6, Igf2, Icam1, and Sp1. Co-treatment with α-naphthoflavone (αNF), a specific antagonist of AhR, prevented almost every 3MC-induced changes. Despite the low dose used in these experiments, daily exposure to 3MC induced changes in both gene expression and epigenomic remodeling, which may lead to premature ovarian failure.
Topics: Acetylation; Animals; Benzoflavones; Chromatin Immunoprecipitation; Down-Regulation; Epigenesis, Genetic; Female; Histones; Methylation; Methylcholanthrene; Ovarian Follicle; Promoter Regions, Genetic; Protein Binding; Protein Processing, Post-Translational; Rats; Rats, Sprague-Dawley; Receptors, Aryl Hydrocarbon; Up-Regulation
PubMed: 29094188
DOI: 10.1007/s00204-017-2096-5 -
The Journal of Biological Chemistry May 1977Induction of hepatic 4-methylumbelliferone UDP-glucuronosyltransferase (EC 2.4.1.17) by polycyclic aromatic compounds, such as 3-methylcholanthrene or...
Genetic regulation of UDP-glucuronosyltransferase induction by polycyclic aromatic compounds in mice. Co-segregation with aryl hydrocarbon (benzo(alpha)pyrene) hydroxylase induction.
Induction of hepatic 4-methylumbelliferone UDP-glucuronosyltransferase (EC 2.4.1.17) by polycyclic aromatic compounds, such as 3-methylcholanthrene or beta-naphthoflavone, occurs in C57BL/6N, A/J, PL/J, C3HeB/FeJ, and BALB/cJ but not in DBA/2N, AU/SsJ, AKR/J, or RF/J inbred strains of mice. This pattern of five responsive and five nonresponsive mouse strains parallels that of the Ah locus, which controls the induction of aryl hydrocarbon (benzo[alpha]pyrene) hydroxylase (EC 1.14.14.2). Induction of the transferase is maximal in C57BL/6N mice with 200 mg of 3-methylcholanthrene/kg body weight; no induction occurs in nonresponsive DBA/2N mice even at a dose of 400 mg/kg. The rise of inducible transferase activity lags 1 or more days behind the rise of inducible hydroxylase activity and peaks 5 days after a single dose of 3-methylcholanthrene. In offspring from the appropriate backcrosses and intercross between C57BL/6N and DBA/2N parent strains, the genetic expression of 3-methylcholanthrene-inducible transferase activity is inherited as an additive (co-dominant) trait. This expression differs distinctly from that of the inducible hydroxylase activity, which is inherited almost exclusively as a single autosomal dominant trait in these same animals. The more potent inducer 2,3,7,8-tetrachlorodibenzo-p-dioxin induces the transferase more than 3-fold in C57BL/6N mice and less than 2-fold in DBA/2N mice, whereas the hydroxylase is induced equally (about 8-fold) in both strains. A dose of 3-methylcholanthrene given 3 days after 2,3,7,8-tetrachlorodibenzo-p-dioxin, at a time when hydroxylase induction in both strains is very high, does not enhance the rise in inducible transferase activity seen in C57BL/6N or DBA/2N mice which have received 2,3,7,8-tetrachlorodibenzo-p-dioxin alone. These data indicate that (a) the inducibility of two metabolically coordinated membrane-bound enzyme activities may be regulated by a single genetic locus, and (b) although the hydroxylase can be fully induced in the nonresponsive DBA/2N strain by 2,3,7,8-tetrachlorodibenzo-p-dioxin prior to 3-methylcholanthrene treatment, metabolites of the 3-methylcholanthrene treatment, metabolites of the 3-methylcholanthrene treatment, metabolites of the 3-methylcholanthrene, presumably present in the liver, are incapable of inducing further the transferase activity. The difference in sensitivity between 3-methylcholanthrene and the more potent inducer 2,3,7,8-tetrachlorodibenzo-p-dioxin for both the hydroxylase and the transferase activities suggests the possibility of a common receptor in regulating both enzyme induction processes.
Topics: Age Factors; Animals; Aryl Hydrocarbon Hydroxylases; Benzopyrene Hydroxylase; Chromosome Mapping; Dose-Response Relationship, Drug; Enzyme Induction; Female; Flavonoids; Glucuronosyltransferase; Male; Methylcholanthrene; Mice; Mice, Inbred Strains; Microsomes, Liver; Polychlorinated Dibenzodioxins; Polycyclic Compounds; Species Specificity
PubMed: 67114
DOI: No ID Found -
European Journal of Biochemistry Jul 1990Hepatocytes from adult and newborn humans were put into primary culture and exposed to phenobarbital, 3-methylcholanthrene, or rifampicin, three well-known inducers of...
Hepatocytes from adult and newborn humans were put into primary culture and exposed to phenobarbital, 3-methylcholanthrene, or rifampicin, three well-known inducers of cytochrome P-450 in animals. The expression of four cytochrome P-450 enzymes (or groups of enzymes, namely P-450 IIIA, P-450 IIC8/9/10, P-450 IIE1, and P-450 IA2) was investigated. These enzymes were found to remain expressed during the period of culture studied. Treatment with the inducers for three days resulted in different responses, depending upon the inducer and the enzyme. Phenobarbital and rifampicin increased P-450 IIC8/9/10 mRNA transcripts and the corresponding protein, while 3-methylcholanthrene was ineffective. Both P-450 IIIA mRNA and protein were strongly induced by rifampicin. All of the hepatocytes were found to synthesize P-450 IIIA in response to rifampicin, as shown by immunoperoxidase staining. P-450 IIIA expression was not affected by phenobarbital and was decreased by 3-methylcholanthrene. P-450s IA2 and IIE1 decreased to 25-50% of the initial level during these cultures. P-450 IA2 and ethoxyresorufin O-deethylase activity (which is a monooxygenase activity related to P-450 IA family) were increased only by 3-methylcholanthrene and did not respond to the other inducers. P-450 IIE1 was not induced by any of these compounds. P-450 IIC8/9/10 and P-450 IIIA mRNA levels were also measured in human hepatocytes from one newborn. P-450 IIC8/9/10 was barely expressed in freshly isolated cells but increased dramatically with time in culture. P-450 IIIA transcripts were abundant in both freshly isolated and cultured cells derived from a newborn. These results clearly demonstrate that human hepatocytes continue to express cytochrome P-450 enzymes and respond to inducers in culture. This model system provides a useful approach for investigating the effects of drugs on maturation and expression of drug-metabolizing enzymes in human liver.
Topics: Adult; Cells, Cultured; Cytochrome P-450 Enzyme System; Enzyme Induction; Gene Expression Regulation, Enzymologic; Humans; Immunoenzyme Techniques; Infant, Newborn; Isoenzymes; Liver; Methylcholanthrene; Phenobarbital; RNA, Messenger; Rifampin
PubMed: 2200675
DOI: 10.1111/j.1432-1033.1990.tb19140.x -
Journal of Biochemistry May 1983The syntheses of two different molecular species of cytochrome P-450, P-450(PB), and P-450(MC), were examined using normal and drug-treated rats, and the rate of...
The syntheses of two different molecular species of cytochrome P-450, P-450(PB), and P-450(MC), were examined using normal and drug-treated rats, and the rate of synthesis was correlated with the drug-induced increase of the amounts in the liver microsomes of treated animals. Phenobarbital (PB) and 3-methylcholanthrene (MC) were used as inducers. The syntheses of cytochrome b5 and NADPH-cytochrome P-450 reductase (fpT) were also examined. In vivo incorporation of L-[3H]leucine indicated a large increase of P-450(PB) synthesis in the livers of PB-treated animals, which reached a plateau value about 18-fold higher than the control level at 12 h. The synthesis of fpT was also stimulated by PB showing a peak value of 3 times the control at 12 h after PB administration, but it returned to the control level afterwards. On the other hand, the syntheses of P-450(MC) and cytochrome b5 did not change at all. Similarly, MC administration selectively induced the synthesis of P-450(MC), which was about 24 times the control at 6 h, whereas those of P-450(PB), cytochrome b5, and fpT were not affected by MC. Analysis of nascent peptides and in vitro translation of polysomes and total liver RNA prepared from control and drug-treated animals were also carried out, and the results of these in vitro experiments confirmed the observations in in vivo incorporation studies. It was found that both free and membrane-bound ribosomes participate in the syntheses of P-450(PB) and P-450(MC) in the case of control animals. PB and MC induced the syntheses of P-450(PB) and P-450(MC) by bound ribosomes but not by free ribosomes, and the contribution of bound ribosomes to the syntheses of these two species of cytochrome P-450 was predominant in the case of drug-treated animals. The molecular sizes of in vitro synthesized P-450(PB) and P-450(MC) were the same as those of authentic samples prepared from liver microsomes.
Topics: Animals; Cytochrome P-450 Enzyme System; Enzyme Induction; Isoenzymes; Leucine; Male; Methylcholanthrene; Microsomes, Liver; Molecular Weight; Phenobarbital; Polyribosomes; Puromycin; Rats; Rats, Inbred Strains
PubMed: 6885729
DOI: 10.1093/oxfordjournals.jbchem.a134271 -
British Journal of Cancer Sep 1949
Topics: Animals; Breast; Breast Neoplasms; Estrogens; Humans; Methylcholanthrene; Mice; Neoplasms
PubMed: 15394414
DOI: 10.1038/bjc.1949.41 -
British Journal of Cancer Dec 1971The subcellular distribution of either [(14)C] or [(3)H]3'-methylcholanthrene was studied in rat liver following a single intraperitoneal injection of the labelled...
The subcellular distribution of either [(14)C] or [(3)H]3'-methylcholanthrene was studied in rat liver following a single intraperitoneal injection of the labelled hydrocarbon 10 hours previously.Adsorbed or non-covalently bound methylcholanthrene and its metabolic derivatives occurred in all cell fractions studied with the exception of purified cell walls. The highest specific activities (d.p.m./mg. protein) were found in washed mitochondria, microsomes and ribosome-free microsomal membranes.Covalent binding of methylcholanthrene and its metabolic derivatives to different cell fractions of rat liver occurs to a small extent and is considered not to be significant. The highest degree of binding occurs in washed mitochondria, microsomes, ribosome-free microsomal membranes and their constituent core proteins.Cell sap which contains non-covalently bound 3'-methylcholanthrene was fractionated into pH 5 enzyme and pH 5 supernatant fractions. The pH 5 enzyme fraction which possesses a high specific activity (d.p.m./mg. protein) was further fractionated with ammonium sulphate into three fractions. The 0-30% ammonium sulphate fraction had the highest specific activity.
Topics: Adsorption; Ammonium Sulfate; Animals; Carbon Isotopes; Cell Fractionation; Cell Membrane; Cell Nucleus; Endoplasmic Reticulum; Hydrogen-Ion Concentration; Injections, Intraperitoneal; Liver; Male; Membranes; Methylcholanthrene; Microsomes, Liver; Mitochondria, Liver; Protein Binding; RNA; Rats; Ribosomes; Tritium
PubMed: 5144545
DOI: 10.1038/bjc.1971.98 -
Cell Biology and Toxicology Jan 20243-Methylcholanthracene (3-MC) is one of the most carcinogenic polycyclic aromatic hydrocarbons (PAHs). Long-term exposure to PAHs has been thought of as an important...
3-Methylcholanthracene (3-MC) is one of the most carcinogenic polycyclic aromatic hydrocarbons (PAHs). Long-term exposure to PAHs has been thought of as an important factor in urothelial tumorigenesis. N-methyladenosine (mA) exists widely in eukaryotic organisms and regulates the expression level of specific genes by regulating mRNA stability, translation efficiency, and nuclear export efficiency. Currently, the potential molecular mechanisms that regulate mA modification for 3-MC carcinogenesis remain unclear. Here, we profiled mRNA, mA, translation and protein level using "-omics" methodologies, including transcriptomes, mA profile, translatomes, and proteomics in 3-MC-transformed urothelial cells and control cells. The key molecules SLC3A2/SLC7A5 were screened and identified in 3-MC-induced uroepithelial transformation. Moreover, SLC7A5/SLC3A2 promoted uroepithelial cells malignant phenotype in vitro and in vivo. Mechanically, METTL3 and ALKBH5 mediated mA modification of SLC3A2/SLC7A5 mRNA in 3-MC-induced uroepithelial transformation by upregulating the translation of SLC3A2/SLC7A5. Furthermore, programmable mA modification of SLC3A2/SLC7A5 mRNA affected the expression of its proteins. Taken together, our results revealed that the mA modification-mediated SLC3A2/SLC7A5 translation promoted 3-MC-induced uroepithelial transformation, suggesting that targeting mA modification of SLC3A2/SLC7A5 may be a potential therapeutic strategy for bladder cancer related to PAHs.
Topics: Humans; Large Neutral Amino Acid-Transporter 1; Methylcholanthrene; Carcinogenesis; Cell Transformation, Neoplastic; Polycyclic Aromatic Hydrocarbons; RNA, Messenger; Methyltransferases; Fusion Regulatory Protein 1, Heavy Chain
PubMed: 38267663
DOI: 10.1007/s10565-024-09846-9