Copper-deficient Group Research Articles

Alterations in plasma lipids, glutathione and homocysteine in relation to dietary copper in rats

Objective: This study aimed to investigate the effect of dietary copper either deficiency or excess on the plasma lipid profile, glutathione (GSH), and homocysteine levels. Design: Three groups of male albino rats were served as control (fed diet containing the required level of Cu; 5.40 mg/kg), copper-deficient (fed diet containing Cu; 0.60 mg/kg) and copper-excess (fed diet containing high level of Cu; 15.0 mg/kg). Materials and Methods: At the end of the experimental period (6 weeks), plasma levels of copper, lipid profile, GSH and homocysteine were estimated in all tested rats groups. Results: There was a significant increase in triacylgycerols, total cholesterol (T.Ch.), high density lipoprotein-cholesterol (HDL-C), very low density lipoprotein- cholesterol, and low density lipoprotein-cholesterol in rats fed a copperdeficient diet compared to control and those fed copper-excess one. In rats fed copper-deficient, HDL-C/T. Ch. ratio was significantly lower than that of the other tested animals. In addition, plasma GSH increased significantly, while plasma homocysteine decreased significantly in copper-deficient group compared to control and copper-excess groups. A significant negative correlation between plasma copper and each of T.Ch. and plasma GSH was observed in control, copper-deficient and copper-excess groups. On the contrary, plasma copper has shown a significant positive correlation with plasma homocysteine in all groups. Conclusion: the present results indicate that feeding of diets rich in bread and powdered milk develop copper-deficiency that resulted in an increase in plasma T.Ch. and triacylglycerols, while decreased HDL-C/T.Ch. ratio. This is representing a risk factor for the development of cardiovascular disorders. However, the body is able to protect itself against these risky changes by increasing the production of antioxidant (GSH) on the expense of homocysteine. Furthermore, copper supplementation can alleviate these degenerative changes.

Copper deprivation in rats induces islet hyperplasia and hepatic metaplasia in the pancreas

Prolonged copper deprivation in rats followed by refeeding with a normal diet has previously been used to induce the appearance of hepatocyte-like cells in the pancreas, but the effects on islet size and morphology have not been determined. In the present study we investigated the distribution of pancreatic alpha- and beta-cells and of hepatocytes in adult rats fed a copper-deficient diet followed by refeeding with a normal diet. Immunohistochemical staining for insulin and glucagon showed that the islets of the copper-deficient group were up to 2.4 times larger in mass compared with controls. The islets were disorganized, with alpha-cells found in multiple layers at the periphery of the islet and sometimes deep in the core. Isolated alpha- and beta-cells were also found in increased numbers in the ductular system. Copper deprivation caused almost complete ablation of the acinar cells, and refeeding induced adipogenesis, acinar regeneration and hepatocyte-like cells. Ductular proliferation and nerve hyperplasia were also present. The hepatocytes tended to be associated with islets or with ducts, rather than with residual pancreatic exocrine tissue. These data show that copper deficiency in rats, as well as inducing the appearance of hepatocytes, is capable of causing islet hyperplasia.

Leukocyte–endothelial adhesion is impaired in the cremaster muscle microcirculation of the copper-deficient rat

Dietary copper deficiency impairs the function of both the vascular endothelium and circulating leukocytes. In the current study, leukocyte–endothelium adhesion was observed in the in vivo cremaster muscle microcirculation of copper-adequate and copper-deficient rats. Male, weanling Sprague–Dawley rats were fed purified diets that were either adequate (5.6 μg/g) or deficient (0.3 μg/g) in copper. Adhesion was stimulated with the inflammatory mediators tumor necrosis factor-α and bradykinin, and the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine. Intravascular adhesion of leukocytes to the vascular endothelium was significantly attenuated in the copper-deficient group in response to all three agonists. These results occurred without any difference in intravascular wall shear rate between the dietary groups. Based on previous work, we propose that the attenuated response is caused by either decreased expression of adhesion molecules on leukocytes and endothelial cells or by inhibition of the endothelial cell calcium signaling associated with copper deficiency.

Neogenesis of pancreatic endocrine cells in copper-deprived rat models.

Transplantation of progenitor cells for regeneration of islet cells could prove invaluable in the treatment of diabetes mellitus. This study provides evidence that in rats maintained on a copper-deficient diet containing the copper-chelating agent tetraethylenepentamine pentahydrochloride, regeneration of single alpha and beta endocrine cells in the ductules and acinar tissue of the adult rat pancreata occurred. These regenerated cells both in the ductules and acinar tissue stained positive for glucagon and insulin similar to cells within the islets and in addition to being reactive to proliferative cellular nuclear antigen, an intracellular marker of active proliferation. In contrast, the control group pancreata did not show any evidence of islet regeneration, proliferation, or proliferative cellular nuclear antigen reactivity pre- or posttransplantation. Transplantation of digested pancreatic tissues from the copper-deficient group into the spleen of syngeneic diabetic rats reversed diabetes, and this was confirmed histologically by demonstrating cells within ductules that stained positively for insulin. This study concludes that copper deprivation contributes to the neogenesis of pancreatic alpha and beta cells in the ductules and acinar tissue of adult pancreas in rat model and that transplanted stem cells maintain their functional capacity in the recipient after transplantation.

β-Carotene 15,15′-Dioxygenase Activity is Responsive to Copper and Iron Concentrations in Rat Small Intestine

Objective: Previous in vitro studies have suggested that β-carotene 15,15′-dioxygenase is an iron-dependent enzyme. However, in vivo, it is difficult to alter iron tissue concentration by varying dietary iron because of homeostatic control. On the other hand, an interaction between iron and copper has been shown, i.e., copper-deficiency results in an increase of iron in rat liver. Therefore, we hypothesized that intestinal iron concentration could be increased by copper-deficiency. Our objective was to examine the effects of iron as affected by dietary copper on β-carotene 15,15′-dioxygenase activity in the small intestine.Methods: Weanling male Sprague-Dawley rats (40 to 45g) were divided into four dietary groups: two copper-adequate groups (6.0 μg Cu/g diet) and two copper-deficient groups (0.6 μg Cu/g) combined with either normal iron (44 μg Fe/g) or high iron (87 μg Fe/g). Iron and copper concentrations were determined by atomic absorption spectrophotometry and the dioxygenase activity by reverse phase HPLC.Results: Intestinal copper concentration was significantly reduced (40%) by the consumption of the copper-deficient diets, but intestinal iron was not changed by doubling dietary iron in rats fed either copper-adequate or copper-deficient diets. However, as hypothesized, the two copper-deficient groups exhibited higher intestinal iron concentration (≥137%, p<0.001) than the copper-adequate controls. In addition, intestinal β-carotene 15,15′-dioxygenase activity was increased by 27% and 106%, respectively, for copper-deficient rats fed either normal or high iron diets, compared to the respective copper-adequate controls (p<0.01). The dioxygenase activity was not significantly affected by dietary iron in either copper-adequate or copper-deficient groups. Finally, the enzyme activity was positively correlated (r=0.67, p<0.0001) with iron concentration and negatively correlated (r=−0.49, p<0.01) with copper concentration in small intestine.Conclusions: Intestinal β-carotene 15,15′-dioxygenase may be an iron-dependent enzyme sensitive to copper status in vivo.

Folate and homocysteine metabolism in copper-deficient rats

To investigate the effect of copper deficiency on folate and homocysteine metabolism, we measured plasma, red-cell and hepatic folate, plasma homocysteine and vitamin B-12 concentrations, and hepatic methionine synthase activities in rats. Two groups of male Sprague–Dawley rats were fed semi-purified diets containing either 0.1 mg (copper-deficient group) or 9.2 mg (control group) of copper per kg. After 6 weeks of dietary treatment, copper deficiency was established as evidenced by markedly decreased plasma and hepatic copper concentrations in rats fed the low-copper diet. Plasma, red-cell, hepatic folate, and plasma vitamin B-12 concentrations were similar in both groups, whereas plasma homocysteine concentrations in the copper-deficient group were significantly higher than in the control group ( P<0.05). Copper deficiency resulted in a 21% reduction in hepatic methionine synthase activity as compared to the control group ( P<0.01). This change most likely caused the increased hepatic 5-methyltetrahydrofolate and plasma homocysteine concentrations in the copper-deficient group. Our results indicate that hepatic methionine synthase may be a cuproenzyme, and plasma homocysteine concentrations are influenced by copper nutriture in rats. These data support the concept that copper deficiency can be a risk factor for cardiovascular disease.

Heart Murmurs, Valvular Regurgitation and Electrical Disturbances in Copper-Deficient Genetically Hypertensive, Hypertrophic Cardiomyopathic Rats

Objective: Rats with a genetic tendency to develop hypertensive, hypertrophic cardiomyopathy were fed copper-deficient diets and their cardiac responses were investigated.Methods: Five male weanling rats of the Long-Evans and SHHF/Mcc-facp strains were randomly selected to receive diets containing either adequate quantities of copper (94.5 μmol Cu/kg diet) or reduced quantities of copper (<15.8 μmol Cu/kg diet) for 6 weeks, (n=5 within each group). Echocardiograms and electrocardiograms were recorded and analyzed at the end of the 6-week interval.Results: Electrocardiograms from copper deficient groups showed longer Q-T intervals and increased QRS amplitudes than controls. Both the copper deficient and control SHHF groups demonstrated significant QRS complex prolongation compared to Long-Evans rats. Echocardiography analysis showed significant increases in left ventricular area, free wall dimension, and myocardial cross-sectional areas in rats fed a copper deficient diet. The frequency of systolic cardiac murmurs increased in copper deficient rats and were related to the presence of valvular regurgitation as determined from echocardiography.Discussion: However, the data do not suggest that a copper-deficient diet fed to a strain of rats genetically susceptible to heart disease later in life, hastens or worsens the onset of cardiac disease. The genetic predisposition and copper-deficient states exert independent effects upon the heart.

Femurs from rats fed diets deficient in copper or iron have decreased mechanical strength and altered mineral composition

A study was conducted to evaluate the influence of copper and iron deficiencies upon femur mineral content and biomechanical properties. Radiogrametry and single photon absorptiometry were used to evaluate femur bone mass. Long-Evans male rats were fed purified diets either adequate or deficient in the selected element from weanling until 9 weeks of age. Results demonstrate that in rats fed both the copper and iron restricted diets, the breaking strength was significantly decreased in both femurs. Lower levels of iron and copper were observed in the livers of the respected trace element restricted groups, and femur iron and copper were depressed in both of these groups as well. Femur Cu:Zn was decreased in the copper deficient group and femur zinc levels were elevated in the iron deficient group. Copper and iron restricted rats had smaller cortical and, larger medullary area in a portion of the femur, 1/4 from the distal end, as determined by radiogrametry, but there were no differences at the mid point or proximal portions of the femurs. The influence of iron restriction upon the decreased bone biomechanical strength is a novel finding and deserves further attention, in that iron deficiency anemia is a prevalent public health problem. J. Trace Elem. Exp. Med. 10:197–203, 1997. © 1997 Wiley-Liss, Inc.

Aspects of Cardiomyopathy Are Exacerbated by Elevated Dietary Fat in Copper-Restricted Rats

The objective of this study was to determine if a high fat diet having a 2:1 saturated:polyunsaturated fatty acid ratio exacerbates signs of copper deficiency. Male weanling Long-Evans rats were randomly placed into one of the following treatment groups: adequate copper low fat, adequate copper high fat, deficient copper low fat or deficient copper high fat. The levels of fat used were 31 or 12% of daily energy, and copper concentrations were 94.5 µmol/kg and <15.8 µmol/kg in the copper-adequate and copper-deficient diets, respectively. Cardiac hypertrophy as well as lower liver copper levels and superoxide dismutase activity were observed in both groups of copper-deficient rats. Irrespective of copper level, consumption of the high fat diet resulted in thickening of the interventricular septum and left ventricular free wall. Electrocardiograms revealed that the copper-deficient high fat diet led to a significantly smaller QT interval compared with all other groups. Significantly greater S-wave voltage due to copper deficiency was observed. Significantly lower heart cytochrome c oxidase (CCO) activity was found in the copper-deficient groups with the copper-deficient high fat group showing the lowest activity. Western blots of the cardiac non-myofibrillar fraction demonstrated lower amounts of CCO nuclear encoded peptides in the copper-deficient groups, with the least amount seen in the copper-deficient high fat treatment. These data suggest that a high level of dietary fat exacerbates some of the signs of copper deficiency.

Maternal zinc deficiency, but not copper deficiency or diabetes, results in increased embryonic cell death in the rat: implications for mechanisms underlying abnormal development.

The mechanisms underlying the teratogenicity of maternal copper deficiency, zinc deficiency, and diabetes are largely unknown. Here we investigated whether these insults are associated with altered patterns of cell death in gestation day (GD) 11.0 rat embryos. Four weeks prior to mating, rats in the copper-deficient group (CuD) were fed a copper-deficient diet supplemented with the chelator, triethylenetetramine, to facilitate the depletion of tissue copper stores. Rats in this group were switched to a triethylenetetramine-free copper-deficient diet 1 week prior to mating. Dams in the diabetic and control groups were fed a control (8 micrograms copper, 25 micrograms zinc/g) diet throughout the study. On GD 3.0, one subset of the control dams was assigned to the zinc-deficient group (ZnD) and fed a zinc-deficient diet. A second subset of control dams was assigned to a restricted fed group and fed the control diet in quantities consumed by the zinc-deficient dams. Litters were taken by cesarean section on GD 11.0. Embryos were examined for gross morphology and assessed for patterns of cell death using Nile blue sulfate. Embryos from the CuD dams were characterized by edematous hindbrain. Embryos from the diabetic group were characterized by delayed development. Altered patterns of cell death were only detected in embryos from the ZnD dams. Within the ZnD group, embryos were either characterized by small size, edematous head region, and control patterns of cell death, or normal size, normal morphology, and increased cell death. These different patterns of morphology and cell death in the embryos of ZnD dams were associated with different patterns of maternal food intake.(ABSTRACT TRUNCATED AT 250 WORDS)

Copper deficiency affects selenoglutathione peroxidase and selenodeiodinase activities and antioxidant defense in weanling rats

Copper deficiency has been postulated result in low selenoglutathione peroxidase (Se-GSHPx) activity, secondary to alterations in the antioxidant defense system. Type I iodothyronine 5'-deiodinase contains selenium; because it is not part of the antioxidant defense system its measurement provides a way to evaluate the influence of copper on selenoenzymes independent of the antioxidant system. Weanling rats were fed the control diet (125.9 nmol Cu/g diet), copper-deficient diet (7.9 nmol Cu/g diet), or the control diet restricted to the intake of the deficient rats (restrict-fed), for 21 d. Rats fed the copper-deficient diet had cardiomegaly, low hematocrit values, and low tissue copper concentrations, but normal liver selenium concentrations. Liver and plasma Se-GSHPx activities were lowest in the deficient rats. Non-Se-GSHPx activity was similar between control and copper-deficient groups. Liver selenodeiodinase activity was lowest in the copper-deficient rats; this reduction was functionally significant as evidenced by low plasma 3,3',5-triiodothyronine and high plasma 3,3',5'-triiodothyronine concentrations.

Isolated Hearts from Copper-Deficient Rats Exhibit Improved Postischemic Contractile Performance

Dietary copper deficiency affects a number of enzymes, the function of which may influence the outcome of myocardial ischemia-reperfusion injury. Male weanling rats were fed diets that were adequate (> 5 mg/kg) or deficient (< 1 mg/kg) in copper. After 4 wk, the rats' hearts were isolated and used to study the effects of ischemia-reperfusion on intraventricular developed pressure (DevP), positive and negative rates of intraventricular pressure change (+dp/dt and -dp/dt) and release of lactate dehydrogenase and creatine kinase from the heart. The ischemia-perfusion protocol included a 15-min equilibration period, 30 min of warm, total ischemia and reperfusion for 30 min. Preischemic hearts from copper-deficient rats produced lower DevP than hearts from copper-adequate rats at all levels of preload. However, postischemic recovery of DevP was significantly greater in the hearts of the copper-deficient group. Furthermore, the postischemic patterns of lactate dehydrogenase and creatine kinase release in the two groups were significantly different. These findings indicate that, although dietary copper deficiency adversely affects a number of enzymatic systems, the functional recovery of hearts subjected to ischemia-reperfusion injury is improved when the diet is restricted in copper.

Respiratory Distress Syndrome in Copper Deficiency: An Experimental Model Developed in Rats

An experimental model has been developed to investigate the effect of copper deficiency on lung maturity in the newborn rat. Three groups of female Sprague-Dawley rats were used: the copper-deficient group was fed with a copper-free diet; the control group received a copper-adequate diet, and the pair-fed group was fed with a limited copper diet. After gestation and delivery, 35% of the newborn copper-deficient group showed respiratory distress syndrome (RDS). The neonatal lungs were isolated and processed for ultrastructural and biochemical study: A greater thickness of the air-blood barrier was observed in the lungs of the copper-deficient group, however, no other differences were observed in the rest of the pulmonary structures. Quantitative differences in pulmonary surfactant were not found in the three groups. The thickness of the air-blood barrier might explain the RDS observed in the copper-deficient newborns.

The influence of dietary carbohydrate and deferoxamine on developing copper deficiency of rats

The present investigation was conducted to follow the development of copper deficiency in male rats from weaning (day 0) to day 31 of dietary copper deprivation and to correlate changes in tissue sizes with copper and iron concentrations. Male rats were fed for 31 days from weaning copper-deficient or adequate diets containing fructose or starch. Another copper-deficient group of rats that was fed fructose was treated with deferoxamine. Rats were killed at day 0, 8, 16, 24, and 31 of the study. In general, no correlation could be found between the development of heart hypertrophy, pancreatic and thymic atrophy, and tissue copper concentrations in copper-deficient rats fed fructose. In contrast, in the heart and pancreas a negative correlation existed between tissue size and iron concentration. In addition, anemia preceded heart hypertrophy. Deferoxamine lowered hepatic iron concentrations, ameliorated the anemia, and decreased heart size compared with untreated rats. The data of the present study suggest that tissue atrophy and hypertrophy and the severity of copper deficiency are not solely due to tissue concentrations of iron and/or copper.

Mechanisms of caeruloplasmin biosynthesis in normal and copper-deficient rats

To examine the mechanisms of holo-caeruloplasmin biosynthesis, we measured the serum caeruloplasmin concentration and oxidase activity, hepatic caeruloplasmin mRNA content and hepatocyte caeruloplasmin biosynthesis and secretion in normal and copper-deficient rats. Copper deficiency resulted in a near-complete loss of serum caeruloplasmin oxidase activity, yet only a 60% reduction in serum caeruloplasmin concentration and no change in the abundance of hepatic caeruloplasmin mRNA or the rate of caeruloplasmin biosynthesis. Both interleukin-1 alpha and lipopolysaccharide increased hepatic caeruloplasmin mRNA content and caeruloplasmin biosynthesis in normal and copper-deficient animals, but neither mediator increased caeruloplasmin oxidase activity in the copper-deficient group. Pulse-chase studies in primary hepatocytes from normal and copper-deficient rats revealed that the secretory rates for newly synthesized caeruloplasmin were identical, despite little or no holo-caeruloplasmin synthesis in hepatocytes of copper-deficient rats. We conclude that hepatocyte copper content has no effect on hepatic caeruloplasmin-gene expression or caeruloplasmin biosynthesis and that the incorporation of copper into newly synthesized caeruloplasmin is not a rate-limiting step in the biosynthesis or secretion of the apoprotein from rat hepatocytes.

EFFECT FO DIETARY COPPER DEFICIENCY ON BRAIN CATECHOLAMINES OF NEWBORN RATS

To investigate the effect of dietary copper deficiency on brain catecholamines of newborn rats an experimental model was developed. Three groups of 10 female Sprague - Dawley rats were used. Group 1, copper deficient group, was fed with a copper-free diet 5 weeks prt-gestation and during gestation until delivery. Group II, the control, received a copper addecuate diet (6ppm). Group III, the pairfed, received a copper addecuate diet, but restringed according to the caloric input of the copper deficient group. Inmediatly after birth, the newborn rats from a total of 7; 4 and 7 litters of the groups I, II and III, respectively were decapited. Eleven assays of each group were performed. For each assay we used 1, 2, 3, or 4 whole brains minus cerebella. Whole brain dopamine and noradrenaline levels were quantified by high performance liquid chromatography with electrochemical detector. Copper deficient group showed a highly significant decrease in brain noradrenaline levels (50% lesser than others two groups: p = 0.0341), whereas dopamine concentrations remained largely unaltered. The levels of brain copper in the newborn rats in group 1 were significantively reduced (p = 0,0001) as well as brain weight (p = 0,0012). The CA1 sector neuronal counting was unaltered, however the girus dentatus counting showed a significant decrease in neuronal cellularity in Group I. We conclude that the materno-fetal copper deficiency altered the synthesis of noradrenaline. This could be a consequence of a functional impairment (possibly Dopamine - - hidroxilase enzyme dismiinished activity), however the possible role of the hypocellularity as the one observed in the girus dentatus sector can not be excluded.

Copper Deficiency and Persistence of the Ductus arteriosus

An experimental model using rats is described, in which a state of copper deficiency was produced in pregnant dams and their offspring. In 100% of the neonates from the copper-deficient group (10/10), 20% (2/10) from the control group, and 40% (4/10) from the pair-fed group, the ductus arteriosus was found to remain patent. These figures were highly significant in statistical terms (X2 test; p less than 0.0009). The possible physiopathology of the persistence of the ductus arteriosus in copper-deficient neonates is discussed.

Dietary copper, simple sugars, and metabolic changes in pigs

Inadequate dietary copper is known to result in undesirable metabolic changes in rats and humans. Abnormal cardiac function, leading to sudden death, is a common finding when copper deficient rats are fed a 62% fructose diet. To further study the apparent mineral-carbohydrate relationship to cardiac physiology, 3 male and 3 female swine were randomly assigned to four groups (6 pigs per group) which were fed low copper (1.5 ppm) or copper supplemented (40 ppm) diets with 20% of calories from either fructose or glucose for 10 weeks. In agreement with results from other animal studies, copper deficient swine exhibited decreased plasma ceruloplasmin, erythrocyte superoxide dismutase and plasma lysyl oxidase activities and lowered serum copper. The copper deficient fructose group had the lowest aortic lysyl oxidase activity and hematocrit when compared to the other groups. The relative heart weight in the copper deficient fructose group was 93% greater than the other three dietary groups. The livers of copper deficient fructose fed pigs were also significantly larger. Two enzymes related to cardiac and hepatic function, aspartate and alanine aminotransferase were also measured. Copper deficiency significantly lowered alanine aminotransferase but there was no dietary effect on aspartate amino-transferase. The results of this project indicate that the pig is a sensitive model for the study of cardiovascular abnormalities which occur when fructose is consumed with a low copper diet.

Comparison of Copper Status in Rats When Dietary Fructose Is Replaced by either Cornstarch or Glucose

The purpose of this study was to determine what levels of starch or glucose replacement for fructose in the copper-deficient diet (copper) can minimize the fructose-copper interaction. Experimental diets contained either 100% fructose as the carbohydrate source, or the fructose was partially replaced with 50% starch, 50% glucose, 75% starch, or 75% glucose. Diets were either copper adequate (7-8 ppm) or inadequate (less than 1 ppm). Male weanling rats were fed their respective diet for 5 weeks and then fasted overnight. After decapitation, blood was collected and liver and heart were removed. Plasma copper was significantly reduced and ceruloplasmin was not detected in all copper-deficient groups. Copper deficiency increased plasma cholesterol, as well as heart and liver weight in the glucose groups, but not in the starch groups. Those organ weights were heavier in glucose-copper than starch-copper rats. Erythrocyte copper-zinc-superoxide dismutase activity was greater in starch-copper rats. Erythrocyte copper-zinc-superoxide dismutase activity was greater in starch-copper than glucose-copper rats regardless of carbohydrate amount. Hepatic copper concentration of the group fed starch-copper was twice levels observed in glucose-copper. The 50% glucose rats had lower hepatic copper than the 75% glucose rats. Hepatic copper-zinc-superoxide dismutase activity showed patterns similar to hepatic copper. Cardiac copper was greater in starch-copper than glucose-copper rats. Cardiac copper-zinc-superoxide dismutase activity was equally reduced in all copper-deficient groups. The 50% starch-replaced diet was more effective in minimizing copper deficiency than the 75% glucose-replaced diet. This poorer improvement of copper deficiency by glucose than starch may partially be due to a more severe reduction of food intake in glucose than in starch diets.

Nutritional copper deficiency does not affect sponge granuloma formation in the rat

Sponge granuloma formation was compared in copper-deficient and copper-sufficient rats following feeding of respective diets for 20, 40, or 60 d. Body weight, total blood hemoglobin, and activities of ceruloplasmin and Cu, Zn-superoxide dismutase in plasma were monitored to ascertain copper deficiency. Mean granuloma weights (mg +/- SEM) in copper-deficient and copper-sufficient groups of rats, respectively, were as follows: 37 +/- 2 and 38 +/- 2 after 20 d, 22 +/- 2 and 23 +/- 2 after 40 d, and 19 +/- 1 and 21 +/- 1 after 60 d on respective diets. Thus, nutritional copper deficiency did not have an effect on sponge granuloma formation in the rat.