Iron body status of rats chronically exposed to cadmium and ethanol

AIMS: The present study was performed to assess the effect of simultaneous long-term exposure to cadmium (Cd) and ethanol on iron (Fe) status of male Wistar rats. METHODS: The animals received drinking water containing 50 mg of Cd/l and/or 10% (w/v) ethanol for 12 weeks. Fe and Cd concentrations in serum (blood), certain tissues, urine and feces were determined by atomic absorption spectrometry. The total pool of Fe was calculated as a sum of its content in liver, spleen, kidneys, heart and brain. Fe bioavailability was evaluated based on its apparent absorption. RESULTS: The daily Cd intake ranged from 3.17 to 4.28 mg/kg (Cd group) and from 2.41 to 3.17 mg/kg (Cd + ethanol group); ethanol consumption ranged from 47.5 to 86.9 g/kg/24 h (ethanol group) and from 47.3 to 63.4 g/kg/24 h (Cd + ethanol group). Exposure to Cd or/and ethanol caused serious disturbances in Fe metabolism, as indicated by Fe body depletion. Both substances, applied alone and in combination, reduced the apparent Fe absorption and decreased its total pool in certain organs, and urinary excretion. However, the Cd- and ethanol-induced changes in the tissue Fe concentrations were different. Cd exposure decreased the concentration of Fe in serum, liver, spleen and femur, whereas ethanol decreased it in the spleen. In rats co-exposed to Cd and ethanol, decreased serum, spleen and brain Fe concentrations were all observed. CONCLUSIONS: The changes in Fe status in rats co-exposed to Cd and ethanol can be explained by the independent action of the two substances, leading to a decrease in Fe bioavailability, or by their interactions, which involves a modifying effect of ethanol on Cd turnover. The results allow the conclusion that ethanol may increase Cd accumulation, making the organism more susceptible to Fe depletion. Alcoholics thus may be at increased risk of disorders in Fe body status.     

The effect of low doses of dietary cadmium oxide on the disposition of trace elements (zinc,copper, iron), hematological parameters,and liver function in rats

The Zn, Cu, and Fe concentrations in selected organs, tissues and in the excreta of male Wistar rats, exposed to dietary CdO (2.80 and 7.15 ppm) for 40 and 60 days, were investigated. Concomitantly hematological values and serum enzyme activities were recorded. Zn levels of spleen, kidney, testes, muscle and feces were not affected by the Cd treatment. After 40 days of Cd exposure, the Zn concentration in the hair decreased, while the Zn level of the lung slightly increased. During the feeding trial, Cd produced an increase of liver Zn by about 24%. Femur Zn decreased and Zn in urine increased after 60 days of exposure to 7.15 ppm Cd. Except in hair and urine, the Cu concentration in all organs and tissues investigated remained unchanged. Hair Cu levels decreased after 40 days of Cd exposure but increased after 60 days. At this time, elevated Cu concentration in urine was recorded. After exposure to 7.15 ppm Cd, the Fe content of the lung, liver, spleen, testes, muscle, femur and blood decreased significantly. After 60 days on the 7.15 ppm diet, highest reductions (30%–60%) of Fe content were recorded in the lung, liver, and spleen. Similar to Zn and Cu, the Fe concentration in urine increased at that time. No changes were found in the Fe content of hair, kidney, and feces. In spite of a disturbed Fe metabolism, an anaemic response of Cd-treated rats was not observed. Hematocrit and hemoglobin remained unchanged and the number of red blood cells slightly increased after 40 days of Cd exposure. While the activity of serum alkaline phosphatase was not affected by dietary Cd, the activities of serum-GOT and serum-GPT increased after exposure to 7.15 ppm Cd indicating disturbed hepatic functions.     

二氧化硫对小鼠超氧化物歧化酶活性的影响

[目的]观察二氧化硫（SO2）对小鼠9种脏器超氧化物歧化酶（SOD）活性的影响。[方法]采用整体动物吸入染毒方式，测定小鼠吸入SO2气体后不同脏器SOD活性的变化。[结果]小鼠吸入较低浓度的SO2后，SOD活性变化因脏器而异；肝，肾，心，脾，脑，小肠，睾丸组织的SOD活性呈下降趋势，肺和胃组织的SOD活性呈上升趋势，但在较高SO2吸入浓度下，9种脏器SOD活性显著下降。[结论]SO2吸入体内会引起机体上述组织抗氧化能力下降。造成机体的氧化损伤。     

Age-Dependent Accumulation of Heavy Metals in Baikal Seal (Phoca sibirica) from the Lake Baikal

Concentrations of Fe, Mn, Zn, Cu, Cd, and Hg were determined in the liver, kidney, and muscle of 60 Baikal seals collected from Lake Baikal in 1992 to investigate age-dependent accumulation. Among essential elements, Fe concentrations in the muscle, liver, and kidney increased with age, suggesting development of diving ability. The concentrations of Mn, Zn, and Cu decreased with age, especially at immature stages. Toxic elements such as Hg and Cd decreased in adult males and thus the male-female difference was clearly observed in their concentrations, which differed from patterns usually found in marine mammals. Such accumulation patterns were due to difference in the feeding rates between males and females under low exposure to Hg and Cd. In addition, a greater excretion of Hg than that of Cd through molting and parturition was estimated. Received: 21 October 1997/Accepted: 2 March 1998     

Balance of magnesium and iron and their content in tissues and body fluids of rats after supplementation with magnesium carbonate

Effect of magnesium on iron and magnesium metabolism in rats were investigated. 96 male Wistar rats were divided into four groups received 2.5; 5.0 and 10.0 mg magnesium daily per kg of body weight--dissolved in 2%--solution of arabic gum (tests groups) or clear 2%--solution of arabic gum (test group) for 4 weeks and the next 4 weeks without supplements. Iron concentrations increased in the brain and kidney of the experimental rats, but decreased in the spleen, intestine and liver (2 and 4 weeks only) also in the heart and femur (only 8 week). Percentage of iron retention decreased during the whole experiment. Magnesium concentrations increased in the spleen, liver and intestine of rats. It was shown that at 8 weeks of experiment the magnesium level of heart and femur decreased (only groups received 2.5 mg and 5.0 mg Mg/kg b.w./24 h), but in group received 10.0 mg Mg/kg b.w./24 h increased for all experiment. The apparent retention of magnesium increased in start of the experiment. This results show that oral magnesium supplementation disturbs metabolism of these elements, especially balance of iron.     

卵巢切除合并慢性铝染毒大鼠中枢外某些元素含量的变化及雌激素的干预效应

目的探讨卵巢切除合并慢性铝中毒及雌激素干预对某些元素在中枢外组织分布和尿液排泄的影响。方法6月龄雌性SD大鼠40只,随机等分为卵巢假切组(Sham组)、卵巢切除组(OVX组)、卵巢切除合并慢性铝中毒组(OVX+Al组)、卵巢切除合并慢性铝中毒及尼尔雌醇灌胃组(OVX+Al+E2组)。Sham组,切除腹腔卵巢体积大小的脂肪组织,以普通饲料喂养;OVX组,切除双侧卵巢,以普通饲料喂养;OVX+Al组,双侧卵巢切除,并以25mg/g的AlCl3.6H2O的饲料喂养;OVX+Al+E2组,双侧卵巢切除,以25mg/g的AlCl3.6H2O的饲料喂养并以尼尔雌醇灌胃(1次/周,每次0.125mg/kg)。手术3个月后,代谢笼收集24h尿液,处死动物取组织。用等离子体发射光谱仪测定肝脏、肾脏、心脏、脊髓、胫骨、骨骼肌和尿的硝解溶液中某些元素含量。结果(1)与Sham组比较,OVX组的心脏Zn降低(P<0.001)。(2)与Sham组比较,OVX+Al组的心脏Zn降低(P<0.001),Si升高(P<0.05);胫骨Mg降低(P<0.05);骨骼肌Cu升高(P<0.001),Se、Si降低(P<0.001,P<0.05);脊髓Se降低(P<0.05);肝脏Cu、Zn、Fe降低(P<0.05,P<0.001,P<0.01),Ca升高(P<0.01);尿液Al、Ca、Mg升高(P<0.05,P<0.01,P<0.05)。(3)与OVX组比较,OVX+Al组的心脏Si升高(P<0.05)、Zn降低(P<0.001);胫骨Cu、Mg降低(P<0.05,P<0.05)。(4)与Sham组比较,OVX+Al+E2组的心脏Al、Cd、Si、Se升高(P<0.05,P<0.01,P<0.01,P<0.001);胫骨Se、Cd升高(P<0.01,P<0.001);肾脏Al升高(P<0.05);骨骼肌Mn、Cu升高(P<0.05,P<0.001),Se降低(P<0.001);脊髓Al、Se、Ca降低(P<0.05,P<0.01,P<0.05);肝脏Mn、Zn、Si升高(P<0.01,P<0.05,P<0.05);尿液Cd、Mg、Se、Al、Ca升高(P<0.05,P<0.05,P<0.01,P<0.001,P<0.001)。(5)与OVX+Al组比较,OVX+Al+E2组的心脏Cd、Mn、Se升高(P<0.05,P<0.05,P<0.01);胫骨Al、Mg、Se、Cd、Mn升高(P<0.05,P<0.01,P<0.001,P<0.001,P<0.001);骨骼肌Mn、Cu升高(P<0.05,P<0.001),Se降低(P<0.001);脊髓Se降低(P<0.05);肝脏Al、Ca降低(P<0.05,P<0.01),Cu、Si、Fe、Mg、Mn、Zn升高(P<0.05,P<0.05,P<0.01,P<0.01,P<0.001,P<0.001);尿液Se、Al、Cd、Mg、Si、Ca升高(P<0.05,P<0.05,P<0.05,P<0.05,P<0.05,P<0.01)。结论长期去卵巢可使大鼠心脏Zn向其它组织器官转移。长期去卵巢合并慢性铝中毒影响的中枢外主要脏器是心脏、骨骼肌和肝脏,影响的元素主要是Zn、Si、Cu和Se。慢性铝中毒可使长期去卵巢大鼠的Si向心脏转移,并进一步促进雌激素缺乏导致的心脏Zn的外转移。补充雌激素可以促进铝的尿排泄。     

硒对大鼠组织中硒、镉、锌、铜、锰含量的影响

本文观察了Ｗｉｓｔａｒ雄性大鼠经口摄入不同浓度的亚硒酸钠液，３周后用原子吸收分光光度法测定肝、肾、脾和睾丸中硒、镉、锌、铜和锰的含量。结果表明：给硒后肝、肾组织中硒的含量随着硒剂量的增加而升高；肝、肾、脾中锌的含量升高，而至１０ｍｇ／Ｌ组锌的含量又下降；肾、脾和睾丸中铜、锰的含量升高，肾、脾中锰含量随硒剂量的增加而降低。     

Effect of selenium and molybdenum on methylbenzylnitrosamine-induced esophageal lesions and tissue trace metals in the rat

Thirty-six weanling male Sprague-Dawley rats were randomly assigned to one of four treatment groups: SE rats received 4.0 ppm selenium as sodium selenite in drinking water containing 1% sucrose; 15MO rats received 15 ppm molybdenum as sodium molybdate in the drinking water; 45MO rats received 45 ppm molybdenum in their water; and CON rats received distilled-deionized water containing only 1% sucrose. The esophageal carcinogen methylbenzylnitrosamine (MBN) was administered intragastrically in 10% ethanol twice per week for 5 wk at a dose of 2.5 mg/kg. MBN dosing was followed by a 12-wk period for tumor promotion. After this, heart, lungs, liver, spleen, kidneys, testes, tibia, muscle, brain and esophagus were excised. The esophagus was examined for MBN-induced lesions using dissecting and light microscopes and a portion was analyzed for Se. All other tissues were analyzed for Cu, Zn, Fe and Mn; some were also analyzed for Se and Mo. Most rats had precancerous lesions, and all rats had papillomas. There were no significant differences among the four treatment groups in the incidence and number per rat of precancerous lesions or gross papillomas. The SE group had significantly fewer carcinomas per rat than the other groups. The SE rats exhibited a number of significant differences in tissue trace element concentrations; in particular, they had higher Fe concentrations in heart, kidney and spleen than the other rats. The SE rats also had significantly greater urinary excretion of Mn and Fe, and excretion of the latter elements was significantly correlated with that of selenium.(ABSTRACT TRUNCATED AT 250 WORDS)     

硒镉摄入对大鼠脏器中硒、镉、铜、锌、锰含量的影响

目的：探讨硒镉摄入对大鼠脏器中硒、镉、铜、锌、锰含量的影响。方法：用含5ppm硒、50ppm镉和含5ppm硒＋50ppm镉的水,供3月龄的Wistar雄性大鼠自由饮用,3周后用原子吸收分光光度法测定大鼠肝、肾、脾和睾丸中硒、镉、铜、锌和锰的含量。结果：5ppm硒组大鼠4种组织中硒、铅含量、肝脾组织中锌含量和肾、脾、睾丸组织中铜含量均高于对照组;50ppm镉组大鼠4种组织中镉的含量、肾脾组织中硒的含量和肝脾组织中铜锌含量均高于对照组;经口同时摄入硒、镉时大鼠4种脏器组织中硒的含量明显低于硒组,4种脏器组织中镉的含量明显高于硒组,肝脏组织中锌的含量显著低于镉组,脾脏组织中锌的含量显著低于硒组,肾、脾、睾丸组织中铜的含量低于硒组,肾、睾丸组织中锰的含量低于镉组。     

Availability and toxicological effects of low levels of biologically bound cadmium

Rats were fed a casein based diet containing Cd biologically bound in ryegrass (Lolium multiflorum L. ssp. italicum) for eight weeks. The grass portion in the diet was 20% (w/w). Cd concentrations of the respective diets were (g/g diet): 0.24 (control group Cd=0), 0.85 (group Cd=1) and 2.25 (group Cd=2). After six weeks on the diets, food intake and body weight were reduced by the low dietary Cd concentration (Cd=1), while in treatment group Cd=2 this occurred after 2 weeks. After an 8-week feeding period the concentrations of Cd, Cu, Zn, Fe and Ca in selected organs, tissues and in the excreta of rats beside whole body element contents were determined. While no elevated Cd levels due to the Cd intoxication were found in skin, lung, blood, testes, muscle and urine, Cd concentrations in liver, kidney and spleen increased in a dose-dependent manner. This was also true for whole body Cd and Cd in faeces, the latter being 27.6 fold higher in the high Cd load (Cd=2) as compared to the controls (Cd=0). Highest Cd concentrations were recorded in liver and kidney. Calculated as percentage of the whole body metal content liver Cd increased from 1.49% (Cd=0) to 7.41% (Cd=2) and kidney Cd from 0.65% to 4.87%. While no changes of the Ca levels in all organs and tissues investigated were observed, liver Zn increased and blood Cu decreased. Copper and Zn increased in faeces and decreased in urine. With the exception of skin and lung, a significant loss of Fe was observed in all organs and tissues, which was most evident in treatment group Cd=2. Depending on the Cd dose applied, reduced fecal and urinary Fe excretion occurred. Hematological parameters (hemoglobin, hematocrit, blood glucose) and serum enzyme activities (alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, -glutamyl transferase) were not affected by Cd in a biologically bound form. Serum alanine amino transferase showed slightly lower activities in treatment groups Cd=1 and Cd=2. Analysis of the glucose concentration and the activity of alkaline phosphatase in urine did not reveal any changes due to the Cd intoxication. Accumulation and toxicological effects of Cd biologically bound in ryegrass are discussed in relation to inorganic forms of the metal administered to mammals.     

Accumulation of cadmium in organs of mice by a long-term injection of cadmium and interactions of cadmium with copper, manganese and zinc already present in the animals (author's transl)]

It is well known that the greater part of the administered cadmium is accumulated in liver and kidneys. But, in considering the toxicity of cadmium, it is important to make clear the time pattern of cadmium accumulation not only in liver and kidneys but in the other organs. Male mice were injected subcutaneously 1 mg/kg of cadmium daily for 25 weeks except one day in every week. Five mice at a time were killed in the suitable time during this experiment, and Cd, Cu, Mn, and Zn concentrations in several organs were determined by atomic absorption spectrophotometry. Cadmium content in liver and kidneys increased remarkably during the first 30 days, and it is scarcely increased after that period. Cadmium content in other organs, that is, heart, lungs, spleen, testes and femurs, increased slowly during the first 20 days, and this content increased hardly after that. The results show further that: Cd administered at the early stage accumulated mainly in liver an in kidneys. As Cd concentration in liver and kidneys arrives at saturation, Cd content in other orbans increased remarkably. And, after 30th day, Cd content in all the organs increased little in spite of the continuous injection of Cd. Concentrations of Cu, Mn, and Zn in the organs of mice injected with Cd were as follows: Cu concentration increased significantly in heart, liver, and kidneys, Zn concentration increased in heart, lungs, liver, and kidneys, whereas Mn concentration decreased remarkably in kidneys. Cadmium content in the organs of mice injected with Zn (0.5 mg/kg) or Mn (0.5 mg/kg) together with Cd (1 mg/kg) showed a tendency to increase remarkably compared with single injection of Cd.     

Effect of diet on urinary and fecal excretion of cadmium,copper, and zinc from rats preaccumulated heavily with cadmium

The effects of diets on urinary and fecal excretion of cadmium (Cd), copper (Cu), and zinc (Zn) were examined after loading Cd to a maximum concentration in the livers of rats. The amount of diet and volume of water taken upad libitum by the rats were also traced throughout. The amount of Cd excreted into urine was dramatically increased immediately after changing to a low protein diet, while that excreted into the feces was slightly decreased (not significant). Zn and Cu excreted into the urine were highly and significantly increased in amount by Cd loading but less affected by diets (not significant). However, Zn and Cu excreted into the feces were lowered by the low protein diet due to the low content of the two metals in this diet. Thus, Cd, selectively released from the liver after changing to a low protein diet, was excreted primarily in the urine.     

Effect of cadmium administration and aging on the concentration of essential metals in liver and kidney

To investigate the changes in the concentration of essential metals in organs caused by exposure to cadmium (Cd) and by aging, Cd was administered subcutaneously in single doses of 0.3, 0.9 and 2.7 nig/kg to female rats 10 and 40 weeks of age. The animals were sacrificed on the 7th day after the administration. The concentration of Cd, zinc (Zn), copper (Cu), iron (Fe) and manganese (Mn) in the liver and the kidney was determined and the relations between the concentration of Cd and that of other metals were investigated.1) In 10-week-old rats, the amount of Cd accumulated in the liver and the kidney increased linearly with increasing doses of Cd, while in 40-week-old rats, suppressed accumulation of Cd in the liver and increased accumulation of Cd in the kidney were found after administration of the high dose.2) The concentration of Zn in the liver and the kidney both increased with increasing doses of Cd. There was no age-related difference.3) The concentration of Cu in the liver increased in the animals which received the intermediate and the high dose, irrespective of age. The concentration of Cu in the kidney showed no changes caused by Cd administration or by aging.4) The concentration of Fe in the liver increased in both 10-week-old and 40-week-old rats which received the high dose. The concentration was higher in 40-week-old rats than in 10-week-old rats. The Fe concentration in the kidney and the Mn concentration in the liver and the kidney was not affected by Cd administration or by aging.5) Discriminant analysis, by age, suggested that the amount of metals in the liver and the kidney was more likely to be affected by exposure to Cd in young individuals and less likely to be affected by exposure to Cd with the increase of age.     

Development of iron deficiency decreases zinc requirement of rats

Effects of the development of Fe deficiency on changes in Fe and Zn metabolism and its possible interactions with dietary Zn were determined. Adequate (25 microg/g) and marginally deficient (5 microg/g) Zn diets containing a sufficient (40 microg/g) dietary Fe levels were fed for 2 wk. Thereafter, both dietary Zn groups were fed an Fe-deficient (2.2 microg/g) diet for 4 wk. It was found that the effects of an Fe-deficient diet began to occur 7 and 14 d after feeding the Fe-deficient diet. At this time, tissue Fe concentrations were depleted and rats were unable to maintain hemoglobin levels. The Fe-deficient diet also induced an immediate fall in plasma Fe concentration, transferrin saturation, and apparent Fe absorption, while the concentrations of liver cytochrome c increased as Fe deficiency developed. Decreases in liver and spleen Fe levels, as well as the activities of blood and bone marrow aminolevulinic acid dehydratase (ALA-D, EC 4.2.1.24) were observed 3, 7, and 14 d after feeding the Fe-deficient diet, and thereafter they were increased. On the other hand, the activity of plasma alkaline phosphatase (ALK-P, EC 3.1.3.1) decreased continuously as Fe deficiency progressed. With severe development of Fe deficiency, rats fed the Zn-adequate diet had increased levels of Zn concentration in the plasma, liver, spleen, kidney, and femur, whereas apparent Zn absorption was decreased. The decrease in apparent Zn absorption and the increase in tissue Zn concentration of rats might be related to the lowered Zn requirement, which is associated with the depressed Zn metabolism caused by feeding Fe-deficient diets.     

微波急性辐照对大鼠体内必需元素分布的影响

用Ｘ波段脉冲微波辐照大鼠２ｈ，观察对心、肝、肺、肾、睾丸及眼球中必需元素分布的影响。结果表明，高功率微波辐照后，大鼠眼球中必需元素含量有显著变化，Ｆｅ的含量显著下降（Ｐ＜０．０５），Ｚｎ、Ｃｕ、Ｃａ、Ｍｇ、Ｋ、Ｎａ含量降低非常显著（Ｐ＜０．０１）。心、肺中Ｚｎ含量降低，Ｃｕ显著升高（Ｐ＜０．０５）。各器官中Ｍｇ、Ｎａ含量降低，而肝、肾中Ｃａ含量显著增高（Ｐ＜０．０１）。结果提示，高功率微波急性辐照后可造成大鼠体内必需元素的再分布，尤其眼球中的变化最为显著，这一现象的机制有待进一步深入研究。     

Copper, manganese, zinc, nickel, cadmium and lead in human foetal tissues

1. Concentrations of copper, manganese, zinc, nickel, cadmium and lead were measured in samples of liver, kidney, brain, heart, lung, skeletal muscle and vertebral bone from forty foetuses of 23-43 weeks gestation. 2. Cu concentrations in the liver were up to 100 times those in other tissues, but only those in the brain showed a significant increase with gestational age. 3. Mn concentrations were similar in all tissues; the over-all range was 0.35-9.27 microgram/g dry matter (DM). 4. Concentrations of Zn in the liver were much higher than in other tissues and decreased with gestational age, whereas levels in skeletal muscle increased. 5. In all tissues Ni concentrations were within the range 0.04-2.8 microgram/g DM and levels in kidney and muscle decreased significantly with age. 6. Cd was detected in most of the tissue samples and concentrations were within the range 0.01-0.58 microgram/g DM. 7. Concentrations of Pb, where it was detected, varied from 0.1 to 2.4 microgram/g DM in the soft tissues and from 0.4 to 4.3 microgram/g DM in the bone samples.     

Influence of chronic MnCl2 and EDTA treatment on tissue levels and urinary excretion of trace metals in rats

Rats were chronically exposed interperitoneally to Mn as MnCl₂-4H₂O for 30 days. Treatment was then discontinued and the urinary excretion of metals (Mn, Zn, Fe, Cu) with or without EDTA treatment was monitored. Kidney, testes, brain, and muscle, but not liver, revealed elevated Mn levels due to chronic exposure to the metal alone. In brain, the tegmentum, and striatum accumulated more Mn than the hippocampus. EDTA-treated rats excreted 12x as much Mn/day in urine as those not treated with EDTA; Zn excretion was increased 6x, Fe 2x, and Cu decreased 0.2x. EDTA administration enhanced the natural elimination of excess Mn from skeletal muscle, but not from the other examined tissues. Changes were also observed in the concentrations of other trace metals. Mn treatment was accompanied by decreased hepatic Fe levels, increased Cu levels in the testes and the corpus striatum and hippocampus of the brain, and an increase in Zn, Fe, and Cu in skeletal muscle. Except for the elevated brain Cu, these effects were reversible if Mn treatment was discontinued. A highly significant positive correlation was noted between the urinary excretion of Mn and Fe under the influence of EDTA treatment.     

硒、镉的摄入对大鼠肝细胞器膜元素分布的影响

用扫描电镜Ｘ线能谱仪分析肝细胞器膜元素构成成分和磷硫做参比的相对含量变化，并结合原子吸收法测定肝组织Ｚｎ、Ｃｕ、Ｓｅ、Ｃｄ含量进行对比，观察Ｗｉｓｔａｒ大鼠分别摄入硒（５ｍｇ／Ｌ）、镉（５０ｍｇ／Ｌ）和硒镉（５ｍｇ／Ｌ＋５０ｍｇ／Ｌ）３周后肝细胞器膜元素分布的影响。结果显示：肝细胞器膜的构成元素主要有两种，一种是以含硒为主，经Ｃｄ处理后其Ｃａ、Ｚｎ含量比其它处理组增加更为明显；另一种则以Ｚｎ、Ｃｕ为主，其铜百分值及锌铜百分含量之和以镉组下降最多。膜上各元素峰值的硫磷比值结果为：镉组Ｆｅ、Ｃｄ上升较明显，Ｚｎ以硒镉组上升最甚，Ｃｕ以硒和硒镉组上升较明显。各处理组肝组织Ｃｄ、Ｚｎ含量均有显著性上升，与膜上元素变化趋于一致。     

Induction and metal speciation of metallothionein in wood mice (Apodemus sylvaticus) along a metal pollution gradient

We investigated the binding of Cd, Cu, and Zn to metallothionein (MT) and other metal-binding proteins in free-living wood mice (Apodemus sylvaticus L.) captured in four areas along a metal pollution gradient. We measured total and cytosolic Cd, Cu, and Zn concentrations in mouse liver and kidney by means of inductively coupled plasma-mass spectrometry (ICP-MS). Total (Cu, Cd, Zn)-MT levels were determined in the same tissues by means of the cadmium thiomolybdate saturation assay. Metal speciation of metalloproteins was studied by means of size-exclusion high-performance liquid chromatography-ICP-MS. Liver and kidney of wood mice from the site adjacent to the pollution source showed the highest Cd and Zn concentrations (total and cytosolic) and (Cu, Cd, Zn)-MT levels compared to the other sites farther away from the pollution source. No or only small site differences in tissue Cu concentrations were observed. Almost all the variation (85-95%) in hepatic and renal (Cu, Cd, Zn)-MT levels was explained by the total or cytosolic hepatic Zn and Cd concentration or the renal Cd concentration, respectively. An analysis of the cytosolic metal speciation showed that the Cd-MT, Cu-MT, and Zn-MT fractions in liver and kidney increased significantly with increasing cytosolic metal concentrations. Metals associated with the other cytosolic protein fractions did not increase with increasing exposure. These results illustrate the important role of MT in metal homeostasis and detoxification processes. We conclude that MT is a useful biomarker for environmental metal contamination in free-living wood mice.     

Metallothionein levels in liver and kidney of Canadians--a potential indicator of environmental exposure to cadmium

Liver and kidney cortex samples were obtained from 89 human autopsies for the determination of metallothionein (MT), cadmium (Cd), zinc (Zn), and copper (Cu). An age-dependent increase of Cd, Zn, and Cd/Zn was observed in the kidney; increases peaked at mid-age and were followed by a decline. Cadmium was present at a low constant level in the liver at all ages. The mean concentrations of Cd and Zn were 18.0 and 40.1 micrograms/g wet weight, respectively, in the kidney, and for the liver the values for Cd and Zn were 2.0 and 79.0 micrograms/g wet weight, respectively. A positive linear relationship was observed between Cd or Zn and MT in the kidney and between Zn and MT in the liver. No other correlation was found between Cu and MT in either organs. Similar values were obtained for MT when estimated by Ag-hem and Cd-hem methods.