Effect of maternal diabetes and dietary copper on fetal development in rats

To test whether diabetes associated alterations in copper metabolism contribute to diabetes-induced teratogenicity in rats, pregnancy outcome was compared between diabetic and nondiabetic rats fed either a copper adequate (12 μg/g diet) or low copper diet (1 μg/g diet). The dietary regimen was begun two weeks prior to mating and continued throughout pregnancy. To facilitate the reduction of maternal copper stores in the low copper groups, the low copper diet was supplemented with a copper chelator, triethylenetetraamine, at 1% for one week; the chelator was removed from the diet one week prior to mating. Pregnancy was terminated on gestation day 20. Maternal and fetal tissues were assessed for copper concentrations, the activities of the cuproenzymes copper, zinc superoxide dismutase and ceruloplasmin, and the copper binding protein metallothionein. Dams fed the low copper diet had low tissue copper concentrations, and low plasma ceruloplasmin and erythrocyte superoxide dismutase activities compared to copper-adequate dams. Fetuses in the low copper groups were characterized by low liver copper concentrations. Gross structural and skeletal anomalies were only observed in the diabetic groups; maternal copper intake did not influence the frequency of these anomalies. However, fetuses in the low-copper nondiabetic group, and both diabetic groups, were characterized by low liver copper, zinc superoxide dismutase activity suggesting that fetal copper metabolism was influenced by both copper intake and diabetes.     

Protective effect of copper against cadmium cytotoxicity on cultured vascular endothelial cells.

We investigated the effect of copper on cadmium-induced cytotoxicity on vascular endothelial cells from bovine aorta in a culture system. Cytotoxicity was evaluated by the [3H]adenine release assay and the histological observation. After a 24-h incubation, cadmium exhibited a significant cytotoxicity on confluent cultures of endothelial cells in a dose-dependent manner, while copper only slightly did after a 24-h incubation. It was found that copper (5 microM) significantly decreased cadmium (1 and 2 microM) cytotoxicity; histologically, formation of de-endothelialized areas in the cell layer caused by cadmium was reduced by copper. The accumulation of cadmium in the cell layer was significantly decreased by copper; however, that of copper was unaffected by cadmium. It was therefore suggested that copper significantly protects cadmium-induced cytotoxicity on cultured endothelial cells primarily through decreasing the cellular cadmium accumulation.     

Effects of prolonged copper exposure in the marine gulf toadfish (Opsanus beta) II: copper accumulation, drinking rate and Na+/K+ -ATPase activity in osmoregulatory tissues

Gulf toadfish were exposed to sublethal levels of copper (12.8 or 55.2 microM) for 30 days. Drinking in control fish averaged 1 ml kg(-1)h(-1) but exposure to 55.2 microM copper resulted in a complex biophasic pattern with initial (3 h and 1 day) inhibition of drinking rate, followed by an elevation of drinking rate from day 3 onwards. Drinking led to copper accumulation in the intestinal fluids at levels three to five times higher than the ambient copper concentrations, which in turn resulted in intestinal copper accumulation. The gill exhibited more rapid accumulation of copper than the intestine and contributed to early copper uptake leading to accumulation in internal organs. Muscle, spleen and plasma exhibited little if any disturbance of copper homeostasis while renal copper accumulation was evident at both ambient copper concentrations. The liver exhibited the highest copper concentrations and the greatest copper accumulation of all examined internal organs during exposure to 55.2 microM. Elevated biliary copper excretion was evident from measurements of gall bladder bile copper concentrations and appeared to protect partially against internal accumulation in fish exposed to 12.8 microM copper. No inhibition of Na+/K+ -ATPase activity in either gills or intestine was seen despite copper accumulation in these organs. Calculations of inorganic copper speciation suggest that Cu(CO3)(2)2- complexes which dominate in seawater and intestinal fluids are of limited availability for uptake while the low levels of ionic Cu2+, CuOH+ and CuCO3 may be the forms taken up by the gill and the intestinal epithelium.     

非阻断性镀银铜输精管节育栓置入兔输精管后铜离子释放规律的观察

目的：探讨铜管型输精管内节育栓的节育效果及使用寿命。方法：将自制非阻断性镀银铜输精管节育栓置入家兔输精管内，观察52周内Cu^2 ,Zn^2 ，精子活动率的变化规律。结果：Cu^2 释放的高峰时间，持续时间均高于国内外报道的其它类型的铜输精子管节育栓，且精子活动率的下降极其明显；Zn^2 无明显变化。结论：自制镀银铜输精管节育栓具有良好的节育效果。     

Contributions of rat Ctr1 to the uptake and toxicity of copper and platinum anticancer drugs in dorsal root ganglion neurons

Dorsal root ganglion (DRG) neurons are affected by platinum-induced neurotoxicity and neurodegenerative processes associated with disturbed copper homeostasis and transport. This study aimed to understand the role of copper transporter 1 (Ctr1) in the uptake and toxicity of copper and platinum drugs in cultured rat DRG neurons, and the functional activities of rat Ctr1 (rCtr1) as a membrane transporter of copper and platinum drugs. Heterologous expression of rCtr1 in HEK293 cells (HEK/rCtr1 cells) increased the uptake and cytotoxicity of copper, oxaliplatin, cisplatin and carboplatin, in comparison to isogenic vector-transfected control cells. Cultured rat DRG neurons endogenously expressed rCtr1 protein on their neuronal cell body plasma membranes and cytoplasm, and displayed substantial capacity for taking up copper, but were resistant to copper toxicity. The uptake of copper by both cultured rat DRG neurons and HEK/rCtr1 cells was saturable and inhibited by cold temperature, silver and zinc, consistent with it being mediated by rCtr1. Cultured rat DRG neurons accumulated platinum during their exposure to oxaliplatin and were sensitive to oxaliplatin cytotoxicity. The accumulation of platinum by both cultured rat DRG neurons and HEK/rCtr1 cells, during oxaliplatin exposure, was saturable and temperature dependent, but was inhibited by copper only in HEK/rCtr1 cells. In conclusion, rCtr1 can transport copper and platinum drugs, and sensitizes cells to their cytotoxicities. DRG neurons display substantial capacity for accumulating copper via a transport process mediated by rCtr1, but appear able to resist copper toxicity and use alternative mechanisms to take up oxaliplatin.     

紫胶红色素异常铜含量的研究

关于紫胶原胶的含铜情况过去尚末见报道,应用原子吸收分光光度法测出紫胶原胶的铜含量为9.49ppm。将紫胶原胶分成粗粒胶、细粒胶、粉胶和紫胶虫尸体四个级分,分别测出其铜含量为8.06ppn、13.44ppm、16.38ppm、49.66ppm。 紫胶原胶中的铜高度富集于紫胶虫尸体之中,它是引起紫胶红色素铜污染的主要污染源。从紫胶的生物来源和紫胶红色素的化学本质分析,紫胶原胶中紫胶红色素的铜污染是不可避免的。     

Influence of simultaneous supplementation of zinc and copper during chelation of lead in rats.

The influence of zinc and copper supplementation during chelation therapy to reduce zinc and copper imbalance and promote lead elimination from the body, was investigated in rats poisoned with lead. The simultaneous supplementation of zinc and copper increased urinary lead excretion by calcium disodium ethylenediamine tetraacetic acid (CaNa2EDTA) compared to treatment with CaNa2EDTA alone. Combination therapy was effective in potentiating the depletion of blood and renal lead by CaNa2EDTA and meso 2,3-dimercapto succinic acid (DMSA). Combination therapy was also more effective in reducing hepatic lead by CaNa2EDTA and blood lead by 2,3-dimercapto propane sulphonate (DMPS). Zinc and copper supplementation produced a more effective reversal of inhibited blood delta-aminolevulinic acid dehydratase (ALAD) activity, urinary delta-aminolevulinic acid excretion and depleted body zinc and copper status.     

Physiological effects of copper in the euryhaline copepod Acartia tonsa: waterborne versus waterborne plus dietborne exposure

The physiological effects of waterborne and waterborne plus dietborne copper exposure were determined in the euryhaline copepod Acartia tonsa at different salinities (5, 15 and 30ppt). Copepods were exposed (48h) to a reported 48-h LC50 for copper (CuCl(2)), which had been previously determined under the same experimental conditions. Whole body copper accumulation, ion concentrations (Na(+), Cl(-), Mg(2+)), and Na(+), K(+)-ATPase activity were the endpoints measured in all experimental groups. Feeding rate was also measured in fed experimental groups. In copper-exposed copepods, whole body copper accumulation was dependent on salinity, decreasing as salinity increased. However, it was similar in copepods exposed to waterborne and waterborne plus dietborne copper, irrespective the salinity tested. Waterborne copper exposure induced a disturbance of the whole body Na(+) concentration in all salinities tested. This effect was characterized by an increased whole body Na(+) concentration in seawater (salinity 30ppt) and a decreased whole body Na(+) concentration at lower salinities (5 and 15ppt). The ionoregulatory imbalance in low salinity (5ppt) was associated with an inhibition of the whole body Na(+), K(+)-ATPase activity, as observed in freshwater fish and crustaceans. When copepods were exposed to waterborne plus dietborne copper, the physiological effects described were only observed at a low salinity (5ppt) and were associated with a marked inhibition of the feeding rate. Taken altogether, the data suggest that the physiological effects induced by waterborne copper exposure in A. tonsa acclimated to higher salinities (15 and 30ppt) are due to a combined effect of food restriction and copper exposure. Differential physiological responses to waterborne and waterborne plus dietborne copper cannot be ascribed to differences in whole body copper burden.     

Effects of copper on the binding of agonists and antagonists to muscarinic receptors in rat brain

Studies were performed to assess the effects of copper treatment in vitro on muscarinic binding parameters in rat brain homogenates. Brainstem, an area low in copper, was found to be insensitive to copper treatment as compared to forebrain, a region of relatively high copper content. Inclusion of 3 microM copper in forebrain homogenates decreased the number of sites seen by [3H]-l-quinuclidinyl benzilate (QNB) by 40-50%. Copper-enhanced displacement of bound QNB was noted for agonists and antagonists. Both ligands showed maximal effects at 6 microM copper, although quantitative differences could be determined at any copper level. At levels of maximal effect, the increase in QNB displacement was greater than or less than 50% for agonists and antagonists respectively. Two-site analyses of carbamylcholine (CCH) binding showed that the addition of 1 microM copper to forebrain homogenates increased the percentage of high affinity sites (alpha) from 42 to 70%. The IC50 decreased from 3.1 to 1.7 microM, but the dissociation constants for the high and low affinity sites were not changed. The effect of added copper on CCH binding to muscarinic receptors was reversible with the addition of the copper-chelating agent triethylene tetramine.     

葡萄糖酸铜的急性毒性和药代动力学

应用原子吸收光谱法，以硫酸铜作对照，对葡萄糖酸铜的急性毒性和在家兔体内的组织分布及其药代动力学进行了实验研究。结果表明，葡萄糖酸铜口服毒性小，静注毒性较大，但两者的毒性均较硫酸铜为小，而且葡萄糖酸铜吸收后，在家兔体内５种脏器中铜含量均较硫酸铜高。此两种药物口服均为开放式－宝模型，葡萄糖酸铜较硫酸铜达峰时间短，半衰期短，消除速度快，维持时间短，两者在家兔体内代谢过程不一致。     

Kinetics of copper accumulation in Lessonia nigrescens (Phaeophyceae) under conditions of environmental oxidative stress

Juvenile individuals of the brown kelp Lessonia nigrescens were exposed to a coastal environment chronically impacted by copper mine wastes and currently displaying more than 250 nM of total dissolved copper. The kinetic of copper accumulation in the intra and extracellular compartments was determined and correlated to the oxidative burst resulting from copper-mediated oxidative stress. Accumulation involved an initial adsorption onto the outer cell wall followed by a slower uptake into the cells. A linear pattern of copper uptake over time was found during the first 52 h of exposure, and a steady state was reached at 76 h. The resulting oxidative stress was found to be inefficiently attenuated, and the intracellular level of copper remained sufficiently high to determine a persistently higher than normal level of reactive oxygen species (ROS). Thus, our results strongly suggest that, in L. nigrescens, copper needs to reach an intracellular threshold before oxidative burst develops. Furthermore, it was found that the high ROS levels generated by copper accumulation within the cells persists after the oxidative burst has ceased, suggesting a limited capacity of the algal tissue to buffer the increases of ROS caused by the environmental copper levels.     

The initial mode of action of copper on the cardiac physiology of the blue mussel, Mytilus edulis

Previous studies have shown that low levels of copper (down to 0.8 microM) induce bradycardia in the blue mussel (Mytilus edulis) and that this is not caused by prolonged valve closure. The aim of this study was to determine the precise mechanism responsible. To establish if copper was directly affecting heart cell physiology, recordings of contractions from isolated ventricular strips were made using an isometric force transducer, in response to copper concentrations (as CuCl2) ranging between 1 microM and 1 mM. Inhibition of mechanical activity only occurred at 1 mM copper, suggesting that the copper-induced bradycardia observed in whole animals cannot be attributed to direct cardiotoxicity. Effects of copper on the cardiac nerves were subsequently examined. Following removal of visceral ganglia (from where the cardiac nerves originate), exposure to 12.5 microM copper had no effect on the heart rate of whole animals. The effect of copper on the heart rate of mussels could not be abolished by depletion of the monoamine content of the animal using reserpine. However, pre-treatment of the animals with alpha-bungarotoxin considerably reduced the sensitivity of the heart to copper. These results indicated that the influence of copper on the heart of M. edulis might be mediated by a change in the activity of cholinergic nerves to heart. In the final experiments, mussels were injected with either benzoquinonium or D-tubocurarine, prior to copper exposure, in an attempt to selectively block the inhibitory or excitatory cholinoreceptors of the heart. Only benzoquinonium decreased the susceptibility of the heart to copper, suggesting that copper affects the cardiac activity of blue mussels by stimulating inhibitory cholinergic nerves to the heart.     

Copper-induced lipid peroxidation and hemolysis in whole blood: evidence for a lack of correlation

In order to establish a possible relationship between hemolytic and peroxidant activities of copper ions, lipid peroxidation was studied in plasma and whole blood incubated for 24 h with different concentrations of copper. The lipid peroxidation was investigated by the determination of thiobarbituric acid-reactive species, conjugated dienes and fluorescent lipid chromophores. The copper-induced lipoperoxidation was clearly demonstrated in plasma incubated with high concentrations of copper (12.10(-4) and 20.10(-4) M); in whole blood, all the lipoperoxidation products were increased in the plasma, while the fluorescent lipid chromophores remained unchanged in red cells. With a copper concentration similar to that found in acute copper intoxication (4.10(-4) M) no lipoperoxidation was observed and yet hemolysis occurred, reduced glutathione (GSH) decreased dramatically and methemoglobin (MetHb) increased. From these results, we assume that, despite its prooxidant activity and its capacity to produce lipoperoxidation, it has not been proven that copper ions at pathophysiological concentrations induce hemolysis by an oxidative mechanism.     

Simultaneous use of 1-hydroxybenzotriazole and copper(II) chloride as additives for racemization-free and efficient peptide synthesis by the carbodiimide method

In the carbodiimide mediated coupling of Z-Gly-l -Val-OH with H-l -Val-OMe in DMF, the simultaneous use of HOBt and copper(II) chloride as additives was found to give the desired peptide in a high yield without racemization. In the presence of HOBt, reducing the amount of copper(II) chloride produced a higher yield. Besides improving the coupling efficiency as compared with the case using copper(II) chloride alone as an additive, the present procedure offered another advantage for racemization suppression. Thus, even for the couplings where a low level of racemization was observed in the presence of copper(II) chloride, the simultaneous addition of HOBt and copper(II) chloride resulted in the elimination of racemization. The effectiveness of this new procedure using the two carbodiimide additives in the synthesis of biologically active peptides was assessed by the preparation of a protected Leuenkephalin. In the 4+1 segment condensation using HOBt and copper(II) chloride simultaneously as additives, no racemization was detected and the yield was high enough. The elimination of racemization and improvement of coupling efficiency produced by the present procedure can be attributable to a reduced tendency for the activated forms of the carboxyl component to form a 5(4H)-oxazolone by the action of HOBt, and to the prevention of racemization by copper(II) chloride of the small amount of the oxazolone formed which is not eliminated by the action of HOBt alone.     

Dietary copper enhances the hepatotoxicity of senecio jacobaea in rats

To determine the effects of dietary copper on the toxicity of Senecio jacobaea (tansy ragwort), a plant that contains the hepatotoxic pyrrolizidine alkaloids (PAs), young male rats were fed diets containing 0 or 5% dried tansy ragwort tops and 0 or 5% μg/g copper (as copper sulfate) for 5 weeks. Hepatotoxicity was measured by the activities of plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). Comsumption of diets containing 5% tansy ragwort alone produced a significant reduction in weight gain accompanied by a 122% increase in plasma AST activity, a 106% increase in ALP activity, and a 152% increase in ALT activity, compared to pair-fed controls. When copper was added to the tansy ragwort diet, the activities of both plasma AST and ALT were increased by more than 350%. Plasma ALP activity was also further enhanced by dietary copper in the tansy ragwort-fed animals but to a lower extent. Supplementary copper alone or a reduction in food intake had no significant effect on any of the enzyme activities. The results suggest that copper potentiates the hepatotoxic effects of tansy ragwort in rats.     

Speciation analysis, bioavailability and risk assessment of copper complexes in phytomedicines using flame atomic absorption spectrometry

Octanol (n-C8H17OH), the configuration of which resembles a carbohydrate and lipid, was used as a biomembrane model, and an octanol-water system was adopted to study the distribution of copper in herbal decoctions under the acidity of saliva, gastric juice, bile and intestinal fluid. Octanol- and water-solubility were used for speciation analysis and the bioavailability assessment of copper. The influence of a combination of Aconitum carmichaeli and Paeonia lactiflora at different ratios, the acidity of the digestive site on the species, and the bioavailability and dose of copper were studied. The concentrations of copper in the original herbal materials and in N-octanol- and water-soluble fractions were determined by flame atomic absorption spectrometry following mixed acid digestion. The results showed that the digestive juice acidity, phytomedical composition, and combination ratio of phytomedicines dominated both the species present and the bioavailability of copper. The concentration of octanol-soluble copper could be used to represent the bioavailability assessment of copper in the phytomedicines, and the dosage of copper in the phytomedicines could be designed based on the level of the octanol-soluble copper and the recommended dietary allowance for copper (0.9 mg/day). Risk assessment could be examined through comparison of the level of octanol-soluble copper and the tolerable upper intake level for copper (10 mg /day).     

Differential cytotoxicity of copper ferrite nanoparticles in different human cells

Copper ferrite nanoparticles (NPs) have the potential to be applied in biomedical fields such as cell labeling and hyperthermia. However, there is a lack of information concerning the toxicity of copper ferrite NPs. We explored the cytotoxic potential of copper ferrite NPs in human lung (A549) and liver (HepG2) cells. Copper ferrite NPs were crystalline and almost spherically shaped with an average diameter of 35 nm. Copper ferrite NPs induced dose‐dependent cytotoxicity in both types of cells, evident by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazoliumbromide and neutral red uptake assays. However, we observed a quite different susceptibility in the two kinds of cells regarding toxicity of copper ferrite NPs. Particularly, A549 cells showed higher susceptibility against copper ferrite NP exposure than those of HepG2 cells. Loss of mitochondrial membrane potential due to copper ferrite NP exposure was observed. The mRNA level as well as activity of caspase‐3 enzyme was higher in cells exposed to copper ferrite NPs. Cellular redox status was disturbed as indicated by induction of reactive oxygen species (oxidant) generation and depletion of the glutathione (antioxidant) level. Moreover, cytotoxicity induced by copper ferrite NPs was efficiently prevented by N‐acetylcysteine treatment, which suggests that reactive oxygen species generation might be one of the possible mechanisms of cytotoxicity caused by copper ferrite NPs. To the best of our knowledge, this is the first report showing the cytotoxic potential of copper ferrite NPs in human cells. This study warrants further investigation to explore the mechanisms of differential toxicity of copper ferrite NPs in different types of cells. Copyright © 2016 John Wiley & Sons, Ltd.     

Subneurotoxic copper(II)-induced NF-κB-dependent microglial activation is associated with mitochondrial ROS

Microglia-mediated neuroinflammation and the associated neuronal damage play critical roles in the pathogenesis of neurodegenerative disorders. Evidence shows an elevated concentration of extracellular copper(II) in the brains of these disorders, which may contribute to neuronal death through direct neurotoxicity. Here we explored whether extracellular copper(II) triggers microglial activation. Primary rat microglia and murine microglial cell line BV-2 cells were cultured and treated with copper(II). The content of tumor necrosis factor-α (TNF-α) and nitric oxide in the medium was determined. Extracellular hydrogen peroxide was quantified by a fluorometric assay with Amplex Red. Mitochondrial superoxide was measured by MitoSOX oxidation. At subneurotoxic concentrations, copper(II) treatment induced a dose- and time-dependent release of TNF-α and nitric oxide from microglial cells, and caused an indirect, microglia-mediated neurotoxicity that was blocked by inhibition of TNF-α and nitric oxide production. Copper(II)-initiated microglial activation was accompanied with reduced IкB-α expression as well as phosphorylation and translocation of nuclear factor-κB (NF-κB) p65 and was blocked by NF-κB inhibitors (BAY11-7082 and SC-514). Moreover, copper(II) treatment evoked a rapid release of hydrogen peroxide from microglial cells, an effect that was not affected by NADPH oxidase inhibitors. N-acetyl-cysteine, a scavenger of reactive oxygen species (ROS), abrogated copper(II)-elicited microglial release of TNF-α and nitric oxide and subsequent neurotoxicity. Importantly, mitochondrial production of superoxide, paralleled to extracellular release of hydrogen peroxide, was induced after copper(II) stimulation. Our findings suggest that extracellular copper(II) at subneurotoxic concentrations could trigger NF-κB-dependent microglial activation and subsequent neurotoxicity. NADPH oxidase-independent, mitochondria-derived ROS may be involved in this activation.     

The copper export pump ATP7B modulates the cellular pharmacology of carboplatin in ovarian carcinoma cells

Human tumor cells lines with acquired resistance to cisplatin (DDP) and carboplatin (CBDCA) are often cross-resistant to copper and vice versa, and some DDP-resistant cells overexpress the copper export pump ATP7B. We sought to demonstrate that ATP7B directly mediates resistance to DDP and CBDCA by stably transfecting human carcinoma cells with a vector designed to express ATP7B. Increased expression of ATP7B rendered all three cell lines tested more resistant to a 1-h exposure to DDP (1.6-2.6-fold), CBDCA (1.5-1.6-fold), and copper (1.2-1.4-fold). The effect of ATP7B on the cellular pharmacology of 64Cu and [14C]CBDCA was investigated in more detail using one cell pair (2008 cells transfected with an empty vector or an ATP7B-expressing vector). In the 2008/ATP7B subline, steady-state copper levels were decreased under both basal and copper-supplemented conditions, as was steady-state CBDCA content upon exposure to 50 microM [14C]CBDCA. Over the first 5 min, the average rate of accumulation of copper and CBCDA in the 2008/ATP7B cells was reduced by 37 and 61%, respectively. Efflux was more rapid from 2008/ATP7B cells for both copper and CBDCA. Two-compartment modeling indicated that the second phase of efflux was increased by a factor of 3.9-fold for CBCDA and to an even greater extent for copper. We conclude that expression of ATP7B regulates sensitivity to CBDCA as well as to DDP and copper and that a transporter that normally mediates copper homeostasis modulates the cellular pharmacology of CBDCA.     

Effect of copper loading on various tissue enzymes and brain monoamines in the rat

Three-week-old 50-g rats were injected with 3.75 mg Cu/kg ip. daily for 2, 4 or 6 weeks. Controls received physiological saline. Copper-treated animals showed an increased mortality, and, in survivors, a decrease in body weight. Hepatic copper concentrations increased 17-, 45- and 89-fold after 2,4 and 6 weeks of copper loading, respectively. Dopa decarboxylase (DDC) and monoamine oxidase (MAO) showed a 40% and 14.7% decrease in activity, respectively, after 4 weeks of copper loading but no inhibition after 2 weeks. There was no effect on hepatic succinate dehydrogenase (SDH) or oxidative phosphorylation after 4 weeks of copper administration. After 6 weeks of copper loading, lactate dehydrogenase (LDH), MAO, SDH, and DDC activity were decreased by 15%,25%,29% and 40%, respectively. Malate dehydrogenase (MDH) was unaffected.After 6 weeks of copper loading renal copper concentration increased 14-fold but there was no effect on LDH, SDH, MDH, DDC or MAO.Brain copper increased 35.6% after 6 weeks of copper administration but there was no effect on DDC, MAO, or on concentrations of dopamine, norepinephrine or serotonin (5HT) in this organ. However, the 5-hydroxyindoleacetic acid concentration, an index of the rate of 5HT turnover in the brain, was significantly reduced; this may have been secondary to the stress of copper loading.The adrenal glands of copper-treated rats were markedly increased in weight after 6 weeks; DDC activity was unchanged. The total 5HT content of the small intestine was unchanged after copper treatment.The present results indicate that copper loading can affect enzymes involved in monoamine metabolism and other thiol-containing enzymes, at least in the liver, but only at very high hepatic copper concentrations. The relative protection of liver enzymes and the absence of any effect on renal enzymes from copper may be related to the intracellular distribution and binding of the metal, the localization of the enzymes themselves, and the presence of various protective cellular mechanisms.