• Journal of fish pathology
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• v.10 no.1
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• pp.39-44
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• 1997

Metallothionein is an important and essential protein to control the intracellular concentration of heavy metals, which exist in all organisms from bacteria to vertebrates. Although the detailed functions and induction mechanisms of metallothionein gene have not been clearly characterized until yet, the structure of several metallothionein genes has been revealed. Especially, piscine metallothionein is regarded as an important protein because it is induced by several heavy metal pollutants and environmental stress and it could be determined the comparative amount of heavy metals and the extent of environmental stress by assaying the RNA transcript of metallothionein gene in the method of the quantitative RT-PCR(Reverse Transcriptase Polymerase Chain Reaction). In this study I have characterized the 450 bp PCR fragment of metallothionein gene amplified by using the mixture of internal specific primers and universal 3' end primer. The nucleotide sequence analysis of 450 bp PCR fragment amplified in cDNA library of channel catfish did not show strong homology to other piscine metallothionein genes.

• Toxicological Research
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• v.11 no.1
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• pp.43-49
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• 1995

The effects of metallothionein and cadmium ion on the hepatic aldehyde oxidase activity and brain lipid peroxidation were tested in vitro. The content of brain lipid peroxide at the condition of normal or $300{\mu}M$ Fe(II)-induced was remarkably reduced by the addition of metallothionein in the incubation mixture. The induced content of lipid peroxide by cadmium $(30{\mu}g/ml)$ ion was reduced by metallothionein $(100{\mu}g/ml)$. The activity of aldehyde oxidase was not affected by metallothionein, but cadmium ion $(8.38{\mu}g/ml)$ increased the activity of aldehyde oxidase about 80% compared to the control. The cadmium-induced activity of aldehyde oxidase was restored to the control level by metallothionein or penicillamine.

• Journal of Microbiology and Biotechnology
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• v.17 no.2
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• pp.348-358
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• 2007

Metallothionein, a cysteine-rich stress response protein that is naturally induced by a variety of immunologic stressors, has been shown to suppress autoimmune disorders through mechanisms not yet fully defined. In the present study, we examined the underlying mechanisms by which metallothionein might mediate such regulation of autoimmunity. $Na\ddot{i}ve\;CD4^+$ T cells from metallothionein-deficient mice differentiated to produce significantly less IL-10, $TGF-{\gamma}$, and repressor of GATA, but more $IFN-{\gamma}$ and T-bet, when compared with those from wild-type mice. The levels of IL-4 and GATA-3 production were not different between the two groups of mice. Conversely, treatment with exogenous metallothionein during the priming phase drove $na\ddot{i}ve$ wild-type $CD4^+\;T$ cells to differentiate into cells producing more IL-10 and $TGF-{\beta}$, but less $IFN-{\gamma}$ than untreated cells. Metallothionein-primed cells were hyporesponsive to restimulation, and suppressive to T cell proliferation in an IL-10-dependent manner. Lymphocytes from metallothionein-deficient mice displayed significantly elevated levels of AP-1 and JNK activities in response to stimulation compared with those from wild-type controls. Importantly, transgenic mice overexpressing metallothionein exhibited significantly reduced susceptibility to collagen-induced arthritis and enhanced IL-10 level in the serum, relative to their nontransgenic littermates. Taken together, these data suggest that metallothionein is able to promote the generation of IL-10-and $TGF-{\beta}$-producing type 1 regulatory T-like cells by downregulating JNK-dependent AP-1 activity. Thus, metallothionein may play an important role in the regulation of Th1-dependent autoimmune arthritis, and may represent both a potential target for therapeutic manipulation and a critical element in the diagnostic assessment of disease potential.

• BMB Reports
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• v.28 no.6
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• pp.490-493
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• 1995

We investigated the effect of hydrogen peroxide-treated metallothionein on the hepatic xanthine oxidase activity in vitro. When the metallothionein was preincubated with 1 mM of hydrogen peroxide, the activity of xanthine oxidase and type conversion were elevated dose-dependently by the addition of metallothionein into the reaction mixture. While increasing the treatment of hydrogen peroxide to the $50{\mu}g$of metallothionein, the xanthine oxidase activity and type conversion ratio were remarkably elevated dose dependently compared to the control. When cadmium ion was added to the reaction mixture, the increasing pattern of the enzyme activity was similar to the effect of hydrogen peroxide-treated metallothionein. DTT or penicillamine restored the increasing activity and type conversion of xanthine oxidase by the cadmium ion to the control level.

• Journal of fish pathology
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• v.5 no.2
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• pp.143-152
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• 1992

Metallothionein is an essential and common protein to regulate the intracellular concentration of heavy metals, which exist in most organisms from bacteria to vertebrates. Although the detailed function of metallothianein has not been fully identified until yet, it may be involoved in the cellular protection against the heavy metal toxicity and in the global regulation of several other genes and the expression of metalloproteins. We have cloned the full cDNA clone of metallothionein gene in Channel Catfish by Reverse Transcriptase-Polymerase Chain Reaction(RT-PCR) starting from poly(A)-containing mRNAs. All PCR fragments have been subcloned into EcoRV site of pBluescript SK+ and dT-tailed at Smal site of pUC19, then PCR products are recovered by the double digestion of recombinant plasmids wiht EcoRI and HindIII, which are adjacent to EcoRV site in multicloning sites or by rapid PCR screening. The nucleotide sequence analysis of pMT150(one of the PCR clones) showed high homology with several other piscine metallothionein cDNA genes.

• Biomedical Science Letters
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• v.12 no.1
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• pp.23-27
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• 2006

The rate of metallothionein synthesis on cadmium-poisoned rats reflects the level of toxicity, and also it reduces the toxicity which is caused by the uptake of cadmium. Chlorella supplementation in the diets of the cadmium-poisoned rats decreased the concentration of cadmium in blood and urine compared with the control group. Although the liver and kidneys of rats are major target organs of cadmium and coherence of metallothionein and cadmium, no previous study has determined the correlation between the rate of metallothionein synthesis in the liver and kidneys of rats and dietary supplementation of chlorella with cadmium uptake. This study analyzed total metallothionein level on the tissue of the liver and kidneys, the concentration of cadmium bound to the metallothionein, and the total concentration of cadmium on the tissue of the liver and kidneys after dietary supplementation with 1%, 5%, and 10% dried chlorella and 40 ppm of cadmium to 46 male SD rats (mean weight: $150\pm20\;g$) for 4 weeks. According to the data analysis of the total rate of metallothionein synthesis in the liver and kidneys, the group of SD rats on the supplementation with 1% chlorella and 40 ppm of cadmium showed a rate of $93.2\pm8.9\;ng/g$, a significant decrease of 58.8% compared to that of the control group of SD rats on the supplementation with cadmium only, which showed a rate of $227.3\pm32.5 ng/g$ (P=0.0001). In contrast, no significant difference was observed through the changing of chlorella concentrations between 5% and 10% chlorella supplementation with cadmium. The group supplemented with 1% or greater chlorella levels represented a greater decrease in the total cadmium concentration of the kidney and liver tissues, the amount of total metallothionein synthesis, the amount of metallothionein with binding to cadmium, and the concentration of free cadmium without binding to metallothionein. Consequently, the supplementation of 1% and 5% chlorella was effective in reducing the synthesis of metallothionein for cadmium uptake, but increased the rate of binding of cadmium to metallothionein.

• Toxicological Research
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• v.11 no.2
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• pp.223-227
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• 1995

This study was conducted to investigate the metallothionein (MT) induction by Lonicerae rios in cadmium chloride intoxication. The results were as follows: Generally, detoxication effects by Lonicerae fios extract increased to the increase of extract concentrations. When 90 mg/kg dosage of Lonicerae fios extract was administered, it showed the highest antitoxic effects in metallothionein induction. From the above results, Lonicerae rios extract increased metallothionein concentration and decreased the toxicity of cadmium in liver.

• YAKHAK HOEJI
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• v.35 no.2
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• pp.99-110
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• 1991

This study was initiated to investigate the effects of organic germanium on cadmium and mercury intoxication. The effect was determined by the metallothionein induction in liver and kidney. Male rats (Sprague-Dawley) were treated with CdCI$_{2}$ (2mg/kg), HgCI$_{2}$ (1 mg/kg) and organic germanium (GE-132) (100 mg/kg) in single and in combination via intraperitoneal injection or intragastric administration every other days for 17 days. Experimental animals were sacrificed after 7, 12 and 17 days treatment. The serum transaminase activities (SGOT, SGPT), concentration of metal and metallothionein, metal-binding capacity of metallothionein in liver and kidney were determined and pathomorphological observations were undertaken. The combined treatment of GE-132 and CdCI$_{2}$ significantly decreased the increment of serum transaminase activities in rats treated with CdCI$_{2}$ only, but the combined treatment of GE-132 and HgCI$_{2}$ did not affect to activities of transaminases induced by mercury only. The concentration of metals (Cd and Hg) except Ge in the liver and kidney of rats increased with the time of treatment. Mercury concentration in kidney of rat treated with HgCI$_{2}$ only was significantly higher than the combined treatment of GE-132 and HgCI$_{2}$. The combined treatment of GE-132 and CdCI$_{2}$ significantly increased the concentration of metallothionein in liver compared to the CdCI$_{2}$ only, although the concentration of cadmium in liver were not significantly different between two groups. This indicates that GE-132 decreased toxicity of cadmium in liver by promoting metallothionein induction. There were no significant differences in metallothionein concentration in liver and kidney of rats between the combined treatment of GE-132 and HgCI$_{2}$ and HgCI$_{2}$ only. Metal-binding capacity of metallothionein varied with each time intervals in liver and kidney of metals treated rats except the liver of the combined treatment of GE-132 and CdCI$_{2}$. This finding explains the concentration of metallothionein in liver keeps abreast with the concention of metal. Furthermore, the combined treatment of GE-132and CdCl$_{2}$ revealed pathologically less changes in liver tissue than CdCl$_{2}$ only; the damages of liver cell, such as lobular necrosis and portal inflammation, were relieved and appeared more later. From the above results, organic germanium is considered to have some beneficial effect on the protection of liver from the cadmium intoxication.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.11b
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• pp.42-58
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• 2002

Acute Cd exposure produces hepatotoxicity, whereas chronic Cd exposure produces nephrotoxicity, hematotoxicity, immunotoxicity and bone damage. Previous experiments suggest that the low-molecular-weight, metal-binding protein metallothionein (MT) in liver protects against liver injury, but is responsible for the kidney injury observed after chronic Cd exposure.(omitted)

• The Journal of Korean Medicine
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• v.22 no.1
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• pp.22-32
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• 2001

This study was conducted to investigate the antitoxic effects of Houttuynia cordata THUNB with chloroform and ethyl acetate fractions. The results were as follows: 1. Detoxication effects of chloroform and ethyl acetate fractions of Houttuynia cordata THUNB were increased in proportion to the dosages. Detoxication effects of ethyl acetate fraction of Houttuynia cordata THUNB were higher than chloroform fraction of Houttuynia cordata THUNB's results and detoxication effects in the kidneys were higher than results for the liver. 2. Metallothionein concentrations in the liver were higher than concentrations in the kidneys, and ethyl acetate fraction of Houttuynia cordata THUNB was higher than chloroform fraction of Houttuynia cordata THUNB in induction of metallothionein. 3. After the administration of chloroform and ethyl acetate fractions of Houttuynia cordata THUNB, body weights increased in proportion to chloroform and ethyl acetate fraction s dosage of Houttuynia cordata THUNB but changes of body weight dminished after 3 weeks. From the above results, this study suggests that chloroform and ethyl acetate fraction of Houttuynia cordata THUNB increased metallothionein induction to cadmium intoxication in rat s kidney and liver and decreased the toxicity of cadmium in rats.