• Journal of Pharmaceutical Investigation
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• v.25 no.4
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• pp.313-322
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• 1995

The covalent conjugation of human recombinant superoxide dismutase (hrSOD) with trichloros-triazine activated polyethylene glycol (PEG) 5000 formed soluble conjugates with molecular weight of 92KD, which retained $90{\sim}98%$ of original activity with a markedly prolonged plasma half-life of enzyme activity. The effect of hrSOD-PEG conjugates on acetaminophen (ACP)-induced hepatotoxicity was tested in male rats which were pretreated with 3-methylcholanthrene. HrSOD-PEG conjugates inhibited the hepatotoxicity produced by ACP, on the other hand, native hrSOD had no protective effect. The above results indicated that oxygen radicals might participate in the mechanism of the ACP-induced hepatotoxicity and that polymer conjugated-protein drugs with prolonged half-lives could be employed as an effective therapeutic agent.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.139-139
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• 1998

Effects of TCDD and flavonoids on ethoxyresorufin deethylase in Hepa I cells and MCF-7 human breast cancer cells were examined. TCDD treatment have resulted in the stimulation of ethoxyresorufin deethylase activity based on fluorometry in Hepa I in dose and time dependent manner. 0.1 nM TCDD showed maximal stimulation of ethoxyresorufin deethylase activity and 24 hour treatment also showed maximal stimulation of ethoxyresorufin deethylase activity. In MCF-7 human breast cancer cells, untreated cells showed high basal level of ethoxyresorufin deethylase activity. TCDD treatment to MCF-7 cells resulted minor stimulation of ethoxyresorufin deethylase activity compared to that in Hepa I cells. Various chemicals were tested for ethoxyresorufin deethylase activity in both cell lines. Flavonoids, such as quercetin showed an inhibition of ethoxyresorufin deethylase activity that is stimulated with TCDD or 3-Methylcholanthrene. Estrogen and estrogen metabolites such as 16a-estriol also affects the ethoxyresorufin deethylase activity in MCF-7 cells.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.138-138
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• 1998

Effects of nitric oxide and hypoxia on ethoxyresorufin deethylase in Hepa I cells and MCF-7 human breast cancer cells were examined. TCDD treatment have resulted in the stimulation of ethoxyresorufin deethylase activity based on fluorometry in Hepa I in dose and time dependent manner. 0.1 nM TCDD showed maximal stimulation of ethoxyresorufin deethylase activity and 24 hour treatment also showed maximal stimulation of ethoxyresorufin deethylase activity. In MCF-7 human breast cancer cells, untreated cells showed high basal level of ethoxyresorufin deethylase activity. TCDD treatment to MCF-7 cells resulted minor stimulation of ethoxyresorufin deethylase activity compared to that in Hepa I cells. Nitric oxide and hypoxia inhibit TCDD effects on ethoxyresorufin deethylase activity in both cell lines. And also flavonoids, such as quercetin showed an inhibition of ethoxyresorufin deethylase activity that is stimulated with TCDD or 3-Methylcholanthrene. Estrogen and estrogen metabolite such as 16 a-estriol and 2-hydroxyestradiol also affects the ethoxyresorufin deethylase activity in MCF-7 cells.

• Biomolecules & Therapeutics
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• v.4 no.3
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• pp.280-284
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• 1996

Licorice has been widely used in combination with other herbs or synthetic drugs for various disorders. In an effort to study the effect of licorice roots (Glycyrrhizae Radix, GR) and glycyrrhizin on the hepatic glucuronidation, we have previously found that the pretreatment of GR or glycyrrhizin for 6 days resulted in a marked increase in the enzymatic activity of 3-methylcholanthrene (3-MC)-inducible hepatic UDP-glucuronosyltransferase (UGT) isozyme that has high affinity toward phenolic substrates (p-nitrophenol form, UGTIA) in Sprague-Dawley rats. As an approach to elucidate the mechanism for the enzyme activation by licorice in rat liver, we examined the levels of hepatocellular mRNAs for UGTIA upon the treatment of GR or glycyrrhizin. The hepatic mRNAs were extracted from Sprague-Dawley rats and Wistar rats after the treatment of the methanol extract of GR (1 g/kg, p.o.), glycyrrhizin (23 mg/kg, p.o.) for 6 days, or 3-MC (40 mg/kg, i.p.) for 3 days. Using the UGT1A1 CDNA as a probe, we found that the mRNAs for the enzyme were induced by 3-MC treatment while those were influenced neither by GR nor by glycyrrhizin in both strains of rats. These results indicate that the activation of rat liver UGTI A by licorice and glycyrrhizin was not due to the induction of mRNAs for the enzyme.

• Toxicological Research
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• v.16 no.2
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• pp.95-100
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• 2000

In previous study, both constitutive expression and 3-methylcholanthrene (3MC)-mediated elevation of CYP1A2 mRNA were demonstrated in human hepatoma HepG2 cells by reverse transcription-polymerase chain reaction (RT-PCR), suggesting that HepG2 cells would be appropriate for the study of human CYP1A2 regulation(Chung and Bresnick, 1994). Further studies were conducted to determine the basis of this induction phenomenon that is observed in HepG2 cells. Since CYP1A1 gene, another polycyclic hydrocarbon(PH)-inducible gene, is regulated by PHs through their interactions via receptors with cis-elements, the 5'-flanking region of human CYP 1A2 gene was analyzed to search such responsive elements. The promoter activity of various lengths of CYP1A2 gene sequence (-3203/+58bp) was measured in transiently-transfected HepG2 cells by fusion constructs containing the CAT, hGH or luciferase genes as a reporter. This region of the CYP1A2 gene, although containing a XRE, was only weakly responsive (less than 2 fold induction) to 10 nM of TCDD or 1 $\mu$M 3 MC treatment. This small enhancement of promoter activity is inconsistent with the previous observation, i.e., 12 to 14 fold-enhanced CYP1A2 mRNA from 1 $\mu$M 3 MC treated HepG2 cells, suggesting that additional mechanisms would exist for PH-mediated induction of CYP1A2 in these cells.

• Environmental Mutagens and Carcinogens
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• v.24 no.3
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• pp.143-150
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• 2004

In mammalian, cytochrome P4501A1 (CYP1A1) is very important for metabolism of xenobiotics such as PAHs(Polycyclic aromatic hydrocarbon) and heterocyclic amine, and it is induced by environmental contaminants such as PAHs, TCDD(2,3,7,8-tetrchlorodibenzo-p-dioxin) and 3-MC (3-methylcholanthrene). In fish, like mammalian, when it is exposed to environmental contaminants, they cause specific and sensitive induction of CYP1A. Therefore, induction of CYP1A in fish and mammalian is widely used as a biomarker for exposure of environmental contaminants. In this study, to compare the function of Cyp1a1 in fish with it in mammalian, we have used rainbow trout(Oncorhynchys mykiss) hepatoma cells (RTH-149) and mouse hepatocyte (Hepa-I). in order to examine induction of Cyp1a1 by TCDD, we have used the bioassay system. We examined effects of TCDD on the Cyp1a1-luciferase reporter gene activity, 7-ethoxyresorufin O-deethylase(EROD) activity and Cypa mRNA level.

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.450-455
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• 1996

The genomic DNA was prepared from trout liver which was treated with 3-methycholanthrene, and cloned into lambda EMBL3 at BamHl site. The genomic library was constructed via infections of these recombinant phages into E. coli K802, and screened by the most $5^I$-portion of trout CYP1A1 cDNA. After the screening of $10^9$ clones of the amplified library, 12 positive clones were isolated, and subjected to further screenings. The results of southern blot hybridization of genomic DNA prepared from the positive clone showed the presence of a single gene of CYP1A1, and 3.5 Kb PstI fragment that hybridizes with the most $5^I$-region DNA of CYP1A1 cDNA. The restriction map of PstI fragment was determined by the restriction digestion with various enzymes. The nucleotide sequence of the upstream genomic DNA of CYPIAI was determined by DNA sequencing of exonuclease III unidirectionally deleted PstI fragment DNA using $[^{35}/S]$dATP. This paper presented the upstream genomic DNA of CYP1A1 contained a part of coding region which was about 351 base pairs (from ATG to PstI site at 3563).

• Environmental Mutagens and Carcinogens
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• v.24 no.4
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• pp.155-162
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• 2004

In mammalian, cytochrome P4501A1 (CYP1A1) is very important for metabolism of xenobiotics such as PAHs(Polycyclic aromatic hydrocarbon) and heterocyclic amine, and it is induced by environmental contaminants such as PAHs, TCDD(2,3,7,8-tetrchlorodibenzo-p-dioxin) and 3-MC (3-methylcholanthrene). In fish, like mammalian, when it is exposed to environmental contaminants, they cause specific and sensitive induction of CYP1A. Therefore, induction of CYP1A in fish and mammalian is widely used as a biomarker for exposure of environmental contaminants. In this study, to compare the function of Cyp1a1 in fish with it in mammalian, we have used rainbow trout(Oncorhynchys mykiss) hepatoma cells (RTH-149) and mouse hepatocyte (Hepa-I). in order to examine induction of Cyp1a1 by TCDD, we have used the bioassay system. We examined effects of TCDD on the Cyp1a1-luciferase reporter gene activity, 7-ethoxyresorufin O-deethylase(EROD) activity and Cypa mRNA level.

• YAKHAK HOEJI
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• v.28 no.1
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• pp.53-59
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• 1984

Drug-metabolizing system which has the important role in drug metabolism is localized in smooth endoplasmic reticulum of hepatocytes and is composed of NADPH, NADPH-cytochrome $P_{450}$ reductase, cytochrome $P_{450}$ and others. It is well known that the enzyme system is induced by phenobarbital and methylcholanthrene. Lipid peroxidation is reaction of oxidative deterioration of polyunsaturated lipids. Formation of lipid peroxides in liver microsome has been found to produce degradation of phospholipid, which are major components of microsomal membrane. The relationship between the formation of lipid oxides and the activities of drug-metabolizing enzyme in the liver of rats was reported by several investigators. In this study the effect of riboflavin tetrabutylate, an antioxidant on lipid peroxidation, specially the relationship between lipid peroxidation and drug-metabolizing enzyme system was investigated. In addition the effect of vitamin A derivatives, such as retinoic acid and retinoid on the enzyme was also observed. Results are summarized as followings. 1) The pretretment with riboflavin tetrabutylate inhibited completely the lengthened sleeping time due to $CCl_{4}$ treatment. 2) The increase of TBA value was prevented by the pretreatment with riboflavin tetrabutylate. 3) The pretreatment with riboflavin tetrabutylate also prevented the decrease of drug-metabolizing enzyme caused by $CCl_{4}$. 4) Both retinoic acid and retinoid remarkably decreased the activity of aminopyrine demethylase. Pretreatment of riboflavin tetrabutylate, however, prevented inhibitory effect of retinoic acid on the enzyme activity.

• Toxicological Research
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• v.14 no.4
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• pp.587-594
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• 1998

In order to understand the mechanism if the regulation of CYP 1A1 gene expression and ethoxyresorufin deethylase (EROD) activity in ex vivo system, we have studied the action of TCDD and 3MC in the isolated perfused female rat liver. CYP1A1 mRNA level and EROD activity were measured in rat liver that was isolated and perfused with various chemicals such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3-methylcholanthrene (3MC), 17$\beta$-estradiol (E$_2$), morin. TCDD or 3MC alone perfusion into female rat liver resulted in increase of CYP 1A1 mRNA level and the magnitude of stimulation was six times higher with TCDD treatment than 3MC treatment. However E$_2$ perfusion into female rat liver showed inhibition of CYP 1A1 mRNA level. When 10$^{-8}$ M E$_2$ was administered concomitantly with either 10$^{-9}$ M TCDD or 10$^{-9}$ M 3MC, stimulated CYP 1A1 mRNA by either TCDD or 3MC was inhibited. Morin was examined for its effects on CYP 1A1 mRNA level and result was similar to that was observed with estrogen. EROD activity was also stimulated with either TCDD or 3MC perfusion, and the magnitude of EROD stiumlation was smaller than that of CYP 1A1 mRNA stimulation in response to TCDD or 3MC perfusion. Unlike CYP1A1 mRNA level, stimulation of EROD activity was greater with 3MC than TCDD. Concomitant perfusion either E$_2$ or morin with TCDD or 3MC inhibited 3MC perfusion or TCDD perfusion stimulated EROD activity. These data suggested that TCDD and 3MC might act diffrently in terms of regulation of CYP 1A1 gene expression in rat liver.