Pregnancy-induced mobilization of copper and zinc bound to renal metallothionein in cadmium-loaded rats

Our investigations undertook to examine whether copper (Cu) and zinc (Zn) bound to renal metallothionein (MT) along with cadmium (Cd) in Cd-loaded rats can be mobilized during pregnancy and lactation. Rats of the Wistar strain were injected with Cd. Synthesis of MT containing Cd, Cu and Zn was induced in the kidneys. Concentrations of Cd and essential elements in blood plasma and organs (liver and kidneys) were compared among non-pregnant and pregnant, and Cd-loaded and non-loaded rats at middle and late gestational days and after delivery. Cu bound to renal MT was decreased with gestational age, while Zn was slightly increased. The results indicate that Cu was mobilized and utilized even when the metal was bound to MT in the kidneys of dams. On the other hand, Zn bound to renal MT in Cd-loaded rats was retained and not mobilized during pregnancy. The elution profile of renal MT on an SW column was changed from a typical renal to a mixed profile of renal and hepatic MTs as a result of decreased Cu content in MT. Plasma essential elements changed similarly with gestational age in both concentrations and distributions in non-loaded and Cd-loaded rats. These results indicate that the 3 metals bound to renal MT are dealt with differently during gestation and lactation, and Cu but not Zn is transferred to the fetus, independently of the Cd status of the dam.     

Relationship between ceruloplasmin and Cu status involving metallothionein induced by several heavy metals in the mouse

ICR male mice aged 5 weeks were injected subcutaneously with CdCl₂, Pb(CH₃COO)₂, AgNO₃, CuCl₂, a combination of Cd and Ag compounds, or a combination of Cu and Ag compounds. These injections were carried out 3 times. Twenty-four hours after the last injection, they were sacrificed. Cd injection significantly stimulated serum ceruloplasmin (Cp) activity and Cu concentration, accompanied by an increase in hepatic Cu. Pb injection also slightly increased the Cp level. In contrast, Ag injection markedly decreased both Cp activity and Cu concentration in the serum. Hepatic Cu increased slightly after Ag injection. Using a combination of Cd and Ag, only the Ag effect on the Cp activity appeared. The Cu injection stimulated Cu binding to metallothionein (MT) and bile excretion of Cu, but not Cp release. With a Cu and Ag combination, the effect of Ag on Cp was lost, with a concomitant disappearance of Ag from the Cp fraction in the serum. Our results suggest that in the mouse, Cd and Ag, Cu antagonistic metals, influence different sites of Cp metabolism. Excess hepatic Cu is partly eliminated by excretion of bile and is partly detoxified by MT induction.     

Metal accumulation and metallothionein in two populations of brown trout, Salmo trutta, exposed to different natural water environments during a run-off episode

Cd, Cu and Zn concentrations were measured in ambient water as well as in gills, liver and kidney tissues of two natural populations of brown trout (Salmo trutta) during a run-off episode in two rivers with different metal compositions due to mining pollution. Metallothionein (MT) was also measured in these tissues. The two rivers, Rugla (Cu contaminated) and Naustebekken (Cd and Zn contaminated), are located in two neighboring drainage basins separated by the topographic divide near the city of Røros in the County of Sør-Trøndelag, Norway. In Rugla, the Cu concentration increased from 15 μg/l at the low water level to 41 μg/l during the run-off episode. In Naustebekken, corresponding values for Cd were 90–170 ng/l and those for Zn were 49–91 μg/l. Gill concentrations of Cu and Cd/Zn MT in both populations of native trout clearly reflect the presence of these metals in the rivers during the run-off, in accordance with the hypothesis of protection caused by MT induction. When Rugla trout were transferred to Naustebekken and vice versa, both the amounts of MT itself and the Cu contents reflected the concentration of this metal in the new environment, indicating that MT induction also protects against acutely increased metal levels. The measured levels of MT in both native and transferred trout can account for all the Cd present in the tissues, but not for all of the Cu and Zn. The capacity of MT to regulate Cd and Cu in the trout populations in their natural habitat therefore seems clearly present. Our data also indicate that the MT I and II isoforms may bind metals selectively.     

Mercury accumulation and its distribution to metallothionein in mouse brain after sub-chronic pulse exposure to mercury vapor

Previously we found that exposure to mercury vapor effectively induced metallothionein (MT) biosynthesis in rat brain. Although the induction of not only MT-I/II but also MT-III was evident, the induction rate of the latter was much lower than that of the former. The brain of an MT-null mouse lacks MT-I/II, but has MT-III. Here we examined the effects of sub-chronic pulse exposure to mercury vapor on the brain MT in MT-null mice and their wild type controls. MT-null and wild type mice were preliminarily exposed to mercury vapor for 2 weeks at 0.1 mg Hg/m³ for 1 h/day for 3 days a week, and then exposed for 11 weeks at 4.1 mg Hg/m³ for 30 min/day for 3 days a week. This exposure caused no toxic signs such as abnormal behavior or loss of body weight gain in the mice of either strain throughout the experimental period. Twenty-four hours after the termination of the exposure, mice were sacrificed and brain samples were subjected to mercury analysis, MT assay, and pathological examination. The MT-null mice showed lower accumulation of mercury in the brain than the wild type mice. Mercury exposure resulted in a 70% increase of brain MT in the wild type mice, which was mostly accounted for by the increase in MT-I/II. On the other hand, the brain MT in the MT-null mice increased by 19%, suggesting less reactivity of the MT-III gene to mercury vapor. Although histochemical examination revealed silver-mercury grains in the cytoplasm of nerve cells and glial cells throughout the brains of both strains, no significant difference was observed between the two strains.     

Transfer and accumulation of cadmium,and the level of metallothionein in perfused human placentae

The purpose of the present study was to investigate the effect of perfusion with a medium containing 12 or 24 g Cadmium (as CdCl₂) per ml on this metal's accumulation, transfer rate and metallothionein (MT) level. The experiments were performed with an isolated lobule of a dually-perfused human term placenta. Placental cell integrity and viability were characterised by their morphology and metabolic function, manifested in the tissue's electron microscopic structure and glucose and oxygen (O²) consumption, respectively. Perfusion with 24 g Cd/ml medium for 5 h resulted in significant elevation in MT. The transfer rate of Cd to the fetal side of the placenta was very slow, and not until 40 min after the addition of Cd into the maternal side was a significant increase in the metal's level observed in the fetal perfusate. Thereafter, the level of the metal increased gradually and reached a steady state about 1 h later, at a level which was less than 1/20th of its concentration in the maternal perfusate. There was a 60-fold increase in Cd level in the cytosolic fraction obtained from the Cd-treated samples. At 12 g Cd/ml no significant changes were noted in morphology, metabolic function and MT content. None of the Cd levels caused a signicant change in O² and glucose consumption, in spite of the fact that with the higher Cd dose the microstructure of the tissue showed some pathological changes. The observed elevation in MT may provide the fetus some protection against the harmful effects of the metal.     

Cadmium uptake and induction of metallothionein synthesis in a renal epithelial cell line (LLC-PK1)

LLC-PK₁ cells, an established cell line from pig kidney with proximal tubule properties, were cultivated in vitro at confluence on plastic dishes. They were then exposed (apical side) to inorganic cadmium (CdCl₂, 5 M) for periods ranging between 1 to 24 h. Analysis of the cell supernatant after homogenisation and ultracentrifugation indicated that Cd taken up in the first 3 h was bound to cytosolic high molecular weight proteins, but was redistributed to low molecular weight proteins at later stages. Induction of Cd-metallothionein (Cd-Mt) synthesis, as judged from Cd-Mt binding to a specific anti-Cd-Mt antibody and from the rate of³⁵S-cys incorporation into a specific protein fraction, was apparent 3–6 h after the addition of Cd to the incubation medium.     

Effect of metallothionein core promoter region polymorphism on cadmium, zinc and copper levels in autopsy kidney tissues from a Turkish population

Metallothioneins (MTs) are metal-binding, low molecular weight proteins and are involved in pathophysiological processes like metabolism of essential metals, metal ion homeostasis and detoxification of heavy metals. Metallothionein expression is induced by various heavy metals especially cadmium, mercury and zinc; MTs suppress toxicity of heavy metals by binding themselves to these metals. The aim of this study was to investigate the association between the − 5 A/G metallothionein 2A (MT2A) single nucleotide polymorphism (SNP) and Cd, Zn and Cu levels in the renal cortex from autopsy cases. MT2A core promoter region − 5 A/G SNP was analyzed by PCR-RFLP method using 114 autopsy kidney tissues and the genotype frequencies of this polymorphism were found as 87.7% homozygote typical (AA), 11.4% heterozygote (AG) and 0.9% homozygote atypical (GG). In order to assess the Cd, Zn and Cu levels in the same autopsy kidney tissues, a dual atomic absorption spectrophotometer system was used and the average levels of Cd, Zn and Cu were measured as 95.54 ± 65.58 µg/g, 181.20 ± 87.72 µg/g and 17.14 ± 16.28 µg/g, respectively. As a result, no statistical association was found between the − 5 A/G SNP in the MT2A gene and the Zn and Cu levels in the renal cortex (p > 0.05), but considerably high accumulation of Cd was monitored for individuals having AG (151.24 ± 60.21 µg/g) and GG genotypes (153.09 µg/g) compared with individuals having AA genotype (87.72 ± 62.98 µg/g) (p < 0.05). These results show that the core promoter region polymorphism of metallothionein 2A increases the accumulation of Cd in human renal cortex.     

Copper accumulation and lipid oxidation precede inflammation and myelin lesions in N,N-diethyldithiocarbamate peripheral myelinopathy

Dithiocarbamates have a wide spectrum of applications in industry, agriculture and medicine with new applications being actively investigated. One adverse effect of dithiocarbamates is the neurotoxicity observed in humans and experimental animals. Results from previous studies have suggested that dithiocarbamates elevate copper and promote lipid oxidation within myelin membranes. In the current study, copper levels, lipid oxidation, protein oxidative damage and markers of inflammation were monitored as a function of N,N-diethyldithiocarbamate (DEDC) exposure duration in an established model for DEDC-mediated myelinopathy in the rat. Intra-abdominal administration of DEDC was performed using osmotic pumps for periods of 2, 4, and 8 weeks. Metals in brain, liver and tibial nerve were measured using ICP-MS and lipid oxidation assessed through HPLC measurement of malondialdehyde in tibial nerve, and GC/MS measurement of F(2) isoprostanes in sciatic nerve. Protein oxidative injury of sciatic nerve proteins was evaluated through quantification of 4-hydroxynonenal protein adducts using immunoassay, and inflammation monitored by quantifying levels of IgGs and activated macrophages using immunoassay and immunohistochemistry methods, respectively. Changes in these parameters were then correlated to the onset of structural lesions, determined by light and electron microscopy, to delineate the temporal relationship of copper accumulation and oxidative stress in peripheral nerve to the onset of myelin lesions. The data provide evidence that DEDC mediates lipid oxidation and elevation of total copper in peripheral nerve well before myelin lesions or activated macrophages are evident. This relationship is consistent with copper-mediated oxidative stress contributing to the myelinopathy.     

A copper deficient diet prevents hepatic copper accumulation and dysfunction in Long-Evans Cinnamon (LEC) rats with an abnormal copper metabolism and hereditary hepatitis

 Long-Evans Cinnamon (LEC) rats that develop spontaneous hepatitis due to an inherently abnormal Cu metabolism have recently been established. This investigation concerns the effects of a Cu-deficient diet on the Cu metabolism linked to hepatic injury in LEC rats. The hepatic Cu concentration at 30 days after birth was 94±4 Cu μg/g liver in LEC rats, whereas that of Fischer rats at the same age was 7±1 Cu μg/g. From 30 days after birth, all rats were fed a semisynthetic diet with two different levels of Cu, 0.5 or 30 μg/g food, for 35 days. In LEC rats fed a Cu-deficient diet (0.5 μg/g), the hepatic Cu concentration was 39±7 μg/g. The Cu-normal diet (30 μg/g) LEC group had a concentration of 357±15 μg/g in the hepatic Cu. The group had significantly higher aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT) and γ-glutamyl transferase (GGT) levels than did the LEC rats given the Cu-deficient diet. These results suggest that the occurrence of acute hepatitis in LEC rats can be prevented by feeding the animals a Cu-deficient diet. Received: 18 October 1993 / Accepted: 11 July 1994     

Tissue- and cell-specific expression of metallothionein genes in cadmium- and copper-exposed mussels analyzed by in situ hybridization and RT-PCR

Metallothioneins (MTs) are metal-inducible proteins that can be used as biomarkers of metal exposure. In mussels two families of MT isoforms (MT10 and MT20) have been characterized. In this study, mussels (Mytilus galloprovincialis) were exposed to 200 ppb Cd and 40 ppb Cu for 2 and 9 days to characterize the tissue and isoform specificity of metal-induced MT expression. Non-radioactive in situ hybridization demonstrated that both MT isoforms were mainly transcribed in digestive tubule epithelial cells, especially in basophilic cells. Weaker MT expression was detected in non-ciliated duct cells, stomach and gill epithelial cells, haemocytes, adipogranular cells, spermatic follicles and oocytes. RT-PCR resulted in cloning of a novel M. galloprovincialis isoform homologous to recently cloned Mytilus edulis intron-less MT10B isoform. In gills, Cd only affected MT10 gene expression after 2 days of exposure while increases in MT protein levels occurred at day 9. In the digestive gland, a marked increase of both isoforms, but especially of MT20, was accompanied by increased levels of MT proteins and basophilic cell volume density (Vv(BAS)) after 2 and 9 days and of intralysosomal metal accumulation in digestive cells after 9 days. Conversely, although metal was accumulated in digestive cells lysosomes and the Vv(BAS) increased in Cu-exposed mussels, Cu exposure did not produce an increase of MT gene expression or MT protein levels. These data suggest that MTs are expressed in a tissue-, cell- and isoform-specific way in response to different metals.     

Localization and quantification of Cd- and Cu-specific metallothionein isoform mRNA in cells and organs of the terrestrial gastropod Helix pomatia

A quantitative assay based on real-time detection polymerase chain reaction (rtdPCR) was applied to analyze basal and metal-induced mRNA levels of two metallothionein (MT) isoforms (Cd-MT and Cu-MT) in organs of the terrestrial gastropod Helix pomatia. The results show that specific Cd-MT mRNA levels increase with Cd tissue burden, identifying hepatopancreas and gut as the main organs of Cd accumulation and, accordingly, the predominant organs of Cd-MT mRNA expression. In situ hybridization localized this isoform in epithelial cells of hepatopancreas, gut, and kidney. In contrast to the observed Cd-dependent inducibility of the Cd-binding MT isoform, gene expression of the Cu-binding MT could not be induced by either Cd or Cu exposure. Only very low mRNA amounts of the Cu-MT isoform were found in snail hepatopancreas and kidney, whereas the mantle exhibited high basal mRNA levels of this isoform. In situ localization revealed that the Cu-MT gene expression was restricted to one cell type, the so-called rhogocytes, which are present to various extents in the different organs examined. These results suggest a metal-specific sharing of functions between the two MT isoforms. The Cd-MT isoform apparently plays a crucial role in Cd detoxification, as demonstrated by the inducibility of this isoform, as well as its specific localization in the main metabolic and Cd storing organs. The predominant presence of Cu-MT in rhogocytes of snail mantle strengthens the hypothesis that this isoform may regulate Cu availability in hemocyanin synthesis.     

Involvement of intestinal calcium transporter 1 and metallothionein in cadmium accumulation in the liver and kidney of mice fed a low-calcium diet

Essential metals can affect the metabolism of nonessential metals. Calcium (Ca) is an essential mineral that is commonly lacking in the diet. When we fed 5-week-old male mice for 4 weeks on a purified diet containing 0.005% Ca (CaDF mice), the Ca concentration in the plasma, liver and kidneys did not decreased. Cd accumulation increased in the liver and kidneys of CaDF mice given 1mg/kg Cd orally each day for 5 days, but not in those given intraperitoneal injections of Cd or Cd-metallothionein (Cd-MT). The zinc (Zn) concentration increased significantly in the intestinal cytosol and plasma during the time the mice were fed the low-Ca diet, and expression of both MT-1 and ZnT-1 sharply increased with a similar time course. Intestinal mRNA expression of CaT1, a Ca transporter, was more than 10 times higher in CaDF mice than in controls, although expression of other transporters, including DMT1, decreased in CaDF mice. These results suggest that CaT1 may stimulate the intestinal absorption of Cd and Zn, and some Cd may be distributed to the kidneys along with MT induced by Zn.     

Cadmium,copper and zinc-binding protein (metallothionein) in the liver of the water lizard Triturus pyrrhogaster

A low -M_r copper (Cu) and zinc (Zn)-binding protein was present in the liver of a control water lizard Triturus pyrrhogaster. Cadmium (Cd) accumulated in the liver of the animals after intramuscular injections of Cd salt and was bound to Cu- and Zn-binding protein of a single isoform that had properties characteristic of metallothionein (MT). Effects of Cd loading on several essential elements in the liver and kidney were also determined.     

Tissue‐specific copper accumulation,zinc levels,induction, and purification of metallothionein in freshwater crab Sinopotamon henanense exposed to subacute waterborne copper

Copper (Cu) is one of the most important essential metals for crustaceans, buttoxic in excess. Metallothioneins (MT) are a family of low molecular weight, cysteine‐rich, metal‐binding proteins, which play important roles in metal homeostasis, detoxification, and cytoprotection. In the present study, Sinopotamon henanense were exposed to 0 (controls), 2.86, and 14.3 mg L^?1 waterborne Cu, Cu accumulation, zinc (Zn) levels and MT induction in gills and hepatopancreas were determined with Cd/Hemoglobin saturation assay and atomic absorption spectrophotometry method. Results showed that Cu accumulation and MT levels were both tissue‐specific and revealed some time‐dependent and dose‐dependent, respectively. The highest Cu accumulations of 82.10 ± 16.38 μg g^?1 w wt were observed in the gill after 15 days of 14.3 mg L^?1 Cu exposure, the peak MT induction of 136.16 ± 19.39 μg g^?1 w wt were observed in the hepatopancreas after 3 day of 14.3 mg L^?1 Cu exposure.In addition, the essential metal homeostasis of Zn was disturbed in some ways by subacute Cu exposure. The calculated ratios of actual Cu to theoretical maximum metal bound by MT indicating that the hepatopancreas had much greater Cu‐binding potentials than the gills. Positive correlation were shown between MT induction and Cu accumulation both in hepatopancreas and gills, indicating that MT induction in S. henanense can be considered as a biomarker for subacute waterborne Cu pollution. Furthermore, the Cu induced MT (CuMT) from S. henanense was purified using acetone precipitation (50–80%), followed by gel filtration chromatography and anion exchange chromatography. SDS‐PAGE and time‐of‐flight mass spectrometry analysis showed that S. henanense CuMT possess two isoforms and both mainly existed as monomer and dimmer forms. These present studies will be helpful to increase the database information of heavy metal‐induced MT in terms of crustaceans. © 2012 Wiley Periodicals, Inc. Environ Toxicol 29: 407–417, 2014.     

The importance of metallothionein for the accumulation of copper, zinc and cadmium in environmentally exposed perch, Perca fluviatilis

A field study of the role of metallothionein (MT) in the binding of heavy metals in perch (Perca fluviatilis), exposed to moderate levels of copper, zinc and cadmium, was performed. Perch were sampled at four sites in Sweden in September during two consecutive years. Two sites were located in the vicinity of a brassworks and two outside the emission range. The first year, fish from the two brassworks sites and from one of the uncontaminated sites were collected. The second year, fish from the most contaminated site and from the two uncontaminated sites were caught. The levels of hepatic copper, zinc and cadmium reflected the concentrations of these metals in water and were increased in fish from the two contaminated sites. The level of cadmium in liver was relatively low. MT was induced in liver of perch caught at the most contaminated site. The hepatic MT content in individual livers correlated well to the accumulation of copper (r = 0.85, P less than 0.001) and zinc (r = 0.75, P less than 0.001). There was a low but significant correlation between the levels of MT and cadmium in the liver (r = 0.48, P less than 0.001). The relationship between MT and metals was very similar both years. Subcellular fractionation of the metals in the liver revealed that an induction of MT was followed by an increased amount of copper, zinc and cadmium bound to the protein. The relative fraction of the total hepatic copper and cadmium bound to MT was increased at the most contaminated site, whereas there was no difference in subcellular distribution of zinc between the sites. In perch from the most contaminated site, the portions of hepatic copper, zinc and cadmium found in the cytosolic fraction were 70, 57 and 81%, respectively. Seventy-one % of the copper, 29% of the zinc and 84% of the cadmium found in hepatic cytosol of fish from the same site, eluted together with MT after gel filtration chromatography. The analysis of the subcellular distribution of copper, zinc and cadmium demonstrates that MT is responsible for the binding of a large amount of the total hepatic cellular content of copper and cadmium in perch.     

Molecular modulation of the copper and cisplatin transport function of CTR1 and its interaction with IRS-4

The copper influx transporter CTR1 is also a major influx transporter for cisplatin (cDDP) in tumor cells. It influences the cytotoxicity of cDDP both in vivo and in vitro. Whereas Cu triggers internalization of CTR1 from the plasma membrane, cDDP does not. To investigate the mechanisms of these effects, myc-tagged forms of wild type hCTR1 and variants in which Y103 was converted to alanine, C189 was converted to serine, or the K178/K179 dilysine motif was converted to alanines were re-expressed in mouse embryo cells in which both alleles of CTR1 had been knocked out and also in HEK293T cells. The Y103A mutation and to a lesser extent the C189S mutation reduced internalization of CTR1 induced by Cu while the K178A/K179A had little effect. Both Y103 and C189 were required for Cu and cDDP transport whereas the K178/K179 motif was not. While Y103 lies in an YXXM motif that, when phosphorylated, is a potential docking site for phosphatidylinositol 3-kinase and other proteins involved in endocytosis, Western blot analysis of immunoprecipitated myc-CTR1, and proteomic analysis of peptides derived from CTR1, failed to identify any basal or Cu-induced phosphorylation. However, proteomic analysis did identify an interaction of CTR1 with IRS-4 and this was confirmed by co-immunoprecipitation from HEK cells expressing either FLAG-CTR1 or myc-CTR1. The interaction was greater in the Y103A-expressing cells. We conclude that Y103 is required for the internalization of hCTR1 in response to Cu, that this occurs by a mechanism other than phosphorylation and that mutation of Y103 modulates the interaction with IRS-4.     

Histochemical changes in protein disulphide bonds in rat liver and kidney after chronic cadmium administration,and the possible relation to metallothionein

After chronic exposure to low doses of CdCl₂ an increase in disulphide bonds has been established in rat liver using a specific staining method for disulphide bonds and cytophotometric quantitation. This increase is dependent on doses and length of exposure time. Evidence is presented that this increase might be related to the accumulation of metallothionein or some other cadmium binding protein. Using the same staining method after long exposure to low doses of CdCl₂ a large number of large dark blue stained granules were observed in the proximal tubule cells, with blue stained deposits in the lumen of the proximal and some renal medulla tubules of the kidney.Evidence is presented that this staining pattern corresponds to the destruction of the proximal tubule cell by the cadmium thionein complex.     

Toxicity and accumulation of Copper oxide (CuO) nanoparticles in different life stages of Artemia salina

Metal nanoparticles production rate and its applications have raised concerns about their release and toxicity to the aquatic and terrestrial organisms. The primary size of Copper Oxide nanoparticles (CuO NP’s) was found to be 114 ± 36 nm using Scanning Electron Microscopy (SEM) and a significant increase in the hydrodynamic diameter of CuO NP was seen within 1 h of interaction. The median lethal concentration (LC₅₀) values obtained from the acute toxicity studies on different life stages of Artemia salina was found to be 61.4, 35, 12.2 and 175.2 mg/L for 1d, 2d, 7d old and adult, respectively. The toxicity associated changes in biochemical markers such as Catalase, Reduced glutathione and Glutathione-S-Transferase were evident. The accumulation of Cu nanoparticles into the gut of Artemia salina was the major reason for toxicity. This study demonstrate the toxicity of CuO NPs to Artemia salina, and the obtained results necessitate the detailed investigation on the possible eco-toxicological implication of these nanomaterials.     

Arsenic accumulation, elimination, and interaction with copper, zinc and manganese in liver and kidney of rats

The arsenic accumulation, distribution and influences on metallothionein-1 (MT-1) expression and other trace elements in various organs were examined in rats orally exposed to sodium arsenate (iAs(V)). Rats received a dose of 0, 1, 10 and 100ppm of iAs(V) in drinking water daily for 4- and 16-weeks. Arsenic seems to be distributed in all of the tissues, and was accumulated relatively higher in the spleen, lung and kidney compared to the liver, and much lower in skin and cerebrum. High dose of iAs(V)-exposure significantly increased the concentration of copper in the kidney, but did not influence other trace elements such as zinc and manganese in the liver. The mRNA expression of MT-1 was dose-dependently increased by iAs(V)-exposure in the liver whereas it was decreased in the kidney. These data indicate that arsenic is widely distributed and significantly accumulated in various organs and influences on other trace elements, and also modulates MT-1 expression in the liver and kidney.