• YAKHAK HOEJI
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• v.47 no.4
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• pp.218-223
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• 2003

Effect of taurine treatment on metabolism of glutathione (GSH) was studied in adult male ICR mice. An acute injection of taurine (250 mg/kg, ip) resulted in a significant decline of hepatic GSH level at t = 6 hr, but plasma GSH level was not altered. The activity of GSH-related enzyme in liver, such as GSH peroxidase, GSSG reductase, GSH S-transferases, ${\gamma}$-glutamylcysteine synthetase or ${\gamma}$-glutamyltranspeptidase, was not affected by taurine at t = 2.5 or 6 hr. Plasma cysteine and cystine levels were elevated rapidly following taurine treatment. Hepatic cysteine level was decreased by taurine, reaching a level approximately 70％ of control at t = 4 and 6 hr. In conclusion, the results indicate that an acute dose of taurine decreases hepatic GSH level by reducing the availability of cysteine, an essential substrate for synthesis of this tripeptide in liver. It is also suggested that taurine may decrease the cysteine uptake by competing with this S-amino acid for a non-specific amino acid transporter.

• Journal of Ecology and Environment
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• v.29 no.1
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• pp.61-67
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• 2006

Tomato (Lycopersicon esculentum Mill) seedlings exposed to various concentrations of $CdCl_2(0{\sim}100{\mu}M)$ in a nutrient solution for up to 9 days were analyzed with respect to the thiol changes and oxidative stress. The Cd exposure increased total non-protein thiols (NPT) and cysteine in both leaves and roots, total glutathione in leaves, and the ratios of oxidized glutathione (GSSG)/reduced glutathione (GSH) in both leaves and roots, but decreased the ratio of dehydroascorbate (DASA)/ascorbate(ASA) in leaves. Our results suggest that the Cd-induced GSH depletion due to thiol synthesis and oxidation alters the antioxidant activity of seedlings for $H_2O_2$, and the subsequent $H_2O_2$ accumulationand oxidative stress result in phytotoxicity.

• The Korean Journal of Zoology
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• v.33 no.4
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• pp.476-492
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• 1990

Sodium arsenite (As) aqueous solution containing 4 ppm wss given to male rats for 15 days as drinking water. Electrophoretic pattern of liver cytosol from As-fed rats appeared to be significantly different from that of the control rats. Although the normal protein content of the cytosol fraction of As-fed rat liver was decreased, 8 stress proteins were increased. In liver cytosol fractions of As-treated rat, one kind of arsenic-binding substance (AsBS) was observed. Molecular weight of AsBS was identified to be 500 D and composition of amino acid was glycine, glutamic acid and cysteine. Glutathione (GSH) appeared to bind to arsenic and GSH-As complex showed the same mobility as AsBS on gel filtration chromatography. GSH conjugated As prevented As from inhibiting respiration, conformational change and swelling-contration of mitochondria. According to the above results. it is concluded that in vfuo treated arsenic stimulated synthesis of stress protein, and arsenic-binding substance might be glutathione and have a protective role against arsenic toxicity.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.166-166
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• 2001

Effects of propargylglycine (PPG) treatment on the hepatic glutathione (GSH) synthesis were examined in adult male ICR mice. Administration of PPG (200 mole/kg, ip) to mice resulted in a complete inhibition of the hepatic cystathionine ${\gamma}$ -lyase (C ${\gamma}$ L) activity measured in cytosol fraction for 40 hr after the treatment. A single injection of PPG rapidly reduced the hepatic GSH levels, which appeared to be sustained at least for 40 hr.(omitted)

• Korean Journal of Veterinary Research
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• v.32 no.4
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• pp.629-633
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• 1992

Caffeine이 랫드의 간조직에서 diethylnitrosamine(200mg/kg B.W., DEN)에 의해 유도되는 preneoplastic altered foci형성의 promotion단계에 미치는 효과를 관찰한 바 다음과 같은 결과를 얻었다. Altered foci의 지표로 사용되는 glutathione S-transferase(GST-P)-positive foci의 수는 caffeine 음수 $m{\ell}$당 2mg 병행투여군($3.10{\pm}2.74$) 및 1mg병행 투여군($5.86{\pm}2.83$) 모두에서 DEN 단독투여 대조군($11.55{\pm}5.82$)에 비하여 현저히 낮게 나타났으며 면적 또한 caffeine 2mg 병행투여군($0.13{\pm}0.11$), 1mg 병행투여군($0.21{\pm}0.12$)에서 DEN 단독투여 대조군($0.76{\pm}0.33$)에 비하여 유의성있는 낮은 수치가 관찰되었다. 간 세포배양에서 unscheduled DNA synthesis(UDS)는 DEN($250{\mu}g/m{\ell}$ of medium)단독처리군에 비하여 caffeine($200{\mu}g/m{\ell}$ of medium) 처리시 약 70% 감소하였다. 이러한 결과는 caffeine이 간암발생의 promotion단계에 작용하여 억제효과를 나타냄을 암시하며 이는 DNA회복의 억제와 관계됨을 알 수 있었다.

• Korean Journal of Plant Tissue Culture
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• v.22 no.2
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• pp.65-70
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• 1995

The synthesis of betalain in hairy root cultures of Phytolacca esculenta van Houtte required the light, but the growth of hairy roots was inhibited 5 times under light condition(1500 1X) compared to dark condition. To investigate the growth inhibition of hairy roots under light condition, we surveyed the effects of several antioxidants on growth and betalain production if suspension cultures of hairy roots was increased 1.2-1.4 times under dark condition and 1.3-1.9 times under light condition by the treatment of ascorbic acid, glutathione, $\alpha$-tocopherol, sodium pyrosulfate and propylgallic acid. The betalain production was increased 1.2-2.1 times by antioxidants under light condition. The combination treatment of antioxidants didn't have any significant effect on the growth of hairy roots and betalain synthesis. The antioxidants of the betalain production were more effect under blue light than others. It was discussed that the endogenous oxidants may be produced under blue light.

• Nutrition Research and Practice
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• v.2 no.2
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• pp.80-84
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• 2008

Beneficial effects of dehydroepiandrosterone (DHEA) supplement on age-associated chronic diseases such as cancer, cardiovascular disease, insulin resistance and diabetes, have been reported. However, its mechanism of action in hepatocellular carcinoma in vivo has not been investigated in detail. We have previously shown that during hepatocellular carcinogenesis, DHEA treatment decreases formation of preneoplastic glutathione S-transferase placental form-positive foci in the liver and has antioxidant effects. Here we aimed to determine the mechanism of actions of DHEA, in comparison to vitamin E, in a chemically-induced hepatocellular carcinoma model in rats. Sprague-Dawley rats were administered with control diet without a carcinogen, diets with 1.5% vitamin E, 0.5% DHEA and both of the compounds with a carcinogen for 6 weeks. The doses were previously reported to have anti-cancer effects in animals without known toxicities. With DHEA treatment, cytosolic malate dehydrogenase activities were significantly increased by ${\sim}5$ fold and glucose 6-phosphate dehydrogenase activities were decreased by ${\sim}25%$ compared to carcinogen treated group. Activities of Se-glutathione peroxidase in the cytotol was decreased siguificantly with DHEA treatment, confirming its antioxidative effect. However, liver microsomal cytochrome P-450 content and NADPH-dependent cytochrome P-450 reductase activities were not altered with DHEA treatment. Vitamin E treatment decreased cytosolic Se-glutathione peroxidase activities in accordance with our previous reports. However, vitamin E did not alter glucose 6-phosphate dehydrogenase or malate dehydrogenase activities. Our results suggest that DHEA may have decreased tumor nodule formation and reduced lipid peroxidation as previously reported, possibly by increasing the production of NADPH, a reducing equivalent for NADPH-dependent antioxidant enzymes. DHEA treatment tended to reduce glucose 6-phosphate dehydrogenase activities, which may have resulted in limited supply for de novo synthesis of DNA via inhibiting the hexose monophophaste pathway. Although both DHEA and vitamin E effectively reduced preneoplastic foci in this model, they seemed to fimction in different mechanisms. In conclusion, DHEA may be used to reduce hepatocellular carcinoma growth by targeting NADPH synthesis, cell proliferation and anti-oxidant enzyme activities during tumor growth.

• Biomolecules & Therapeutics
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• v.25 no.4
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• pp.427-433
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• 2017

Previously, we demonstrated that galangin (3,5,7-trihydroxyflavone) protects human keratinocytes against ultraviolet B (UVB)-induced oxidative damage. In this study, we investigated the effect of galangin on induction of antioxidant enzymes involved in synthesis of reduced glutathione (GSH), and investigated the associated upstream signaling cascades. By activating nuclear factor-erythroid 2-related factor (Nrf2), galangin treatment significantly increased expression of glutamate-cysteine ligase catalytic subunit (GCLC) and glutathione synthetase (GSS). This activation of Nrf2 depended on extracellular signal-regulated kinases (ERKs) and protein kinase B (AKT) signaling. Inhibition of GSH in galangin-treated cells attenuated the protective effect of galangin against the deleterious effects of UVB. Our results reveal that galangin protects human keratinocytes by activating ERK/AKT-Nrf2, leading to elevated expression of GSH-synthesizing enzymes.

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.2
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• pp.157-162
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• 2003

The glutathione S-transferase (GSTs) are enzymes responsible for the protection of cells from chemical toxicants and oxidative stress. We describe here the cDNA sequence and mRNA expression of a putative GST from the mole cricket, Gryllotalpa orientalis. The G. orientalis GST cDNA sequences comprised of 621 bp encoding 207 amino acid residues. The multiple sequence alignment of G. orientalis GST gene with other known insect GSTs showed several conserved residues that may be essential for the enzymatic activity of the protein. Phylogenetic analysis of the deduced amino acid sequences of G. orientalis GST gene with other insect GST sequences revealed that the G. orientalis GST gene belongs to class I GST, forming a strong monophyletic group (100% bootstrap value) exclusively for class I GSTs from a diverse insect species. Northern blot analysis confirmed midgut-specific expression at transcriptional level, evidencing the midgut as a site for GST synthesis.

• Toxicological Research
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• v.23 no.2
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• pp.127-133
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• 2007

Metformin is a drug used to lower blood sugar levels in patients with type 2 diabetes via activation of adenosine monophosphate (AMP)-activated protein kinase (AMPK). The primary objective of this study was to investigate whether metformin at the pharmacologically effective concentrations affects the expressions of ${\gamma}$-glutamylcysteine synthetase and phase II antioxidant genes in the H4IIE cell. Treatment of the cells with either metformin or 5-aminoimidazole-4-carboxamide riboside (AICAR) abrogated tert-butylhydroxyquinone (t-BHQ) induction of ${\gamma}$-glutamylcysteine synthetase, a rate limiting enzyme of GSH synthesis. The ability of t-BHQ to induce glutathione S-transferases (GSTs), a major class of phase II detoxifying enzymes that playa critical role in protecting cells from oxidative stress or electrophiles, was also inhibited by the agents. Transcriptional gene repression by metformin was verified by the GSTA2 promoter luciferase assay. Moreover, either metformin or AICAR treatment significantly decreased t-BHQ-dependent induction of other GSTs (i.e., $GST{\mu}$ and $GST{\pi}$ forms). Taken together, our data indicate that metformin treatment may result in the repression of ${\gamma}$-glutamylcysteine synthetase and glutathione S-transferase genes possibly via AMPK activation.