Ascorbic acid supplementation and copper status in rats

The effect of a high concentration (1%, w/w) of ascorbic acid in a Cu-adequate (150 μmol/kg) purified diet was studied in rats. After 6 wk, ascorbic acid had significantly reduced Cu concentrations in muscle and bone. The estimated whole body content of Cu in rats fed ascorbic acid was reduced by 20%. Within 1 d after oral administration of⁶⁴Cu, the recovery of the dose in feces was increased in rats fed ascorbic acid, suggesting that the vitamin depresses intestinal absorption of Cu. After intraperitoneal (ip) administration of⁶⁴Cu, the rate of loss of the dose from the body was decreased in rats fed ascorbic acid. This study suggests that the ascorbic acid induces a decreased efficiency of intestinal Cu absorption, which in turn triggers mechanisms to preserve Cu in the body stores. This is supported by the observation that the feeding of a Cu-deficient diet (5 μmol/kg) had similar effects, although more pronounced.     

Oleic Acid Alleviates Cadmium-Induced Oxidative Damage in Rat by Its Radicals Scavenging Activity

Toxic heavy metal cadmium wildly pollutes the environment and threats the human health. Effective treatment of cadmium-induced toxicity and organ damage is an important issue. Cadmium causes organ damage through inducing oxidative stress. Our previous study also found oleic acid (OA) synthesis-related gene can confer resistance to cadmium and alleviate cadmium-induced stress in yeast. However, its alleviation mechanism on cadmium stress especially in animals is still unclear. In this study, the alleviative effects of OA on cadmium and cadmium-induced oxidative stress in rats were investigated. Oral administration of 10, 20, and 30 mg/kg/day OA can significantly increase the survival rate of rats intraperitoneally injected with 30 mg/kg/day cadmium continuously for 7 days. Similar to ascorbic acid (AA), OA can significantly reduce the cadmium-induced lipid peroxidation in multiple organs of rats. The investigation of OA on superoxide dismutase (SOD) activity showed that OA increased the SOD activity of cadmium-treated rat organs. More important, OA reduced the level of superoxide radical O²⁻ of cadmium-treated rat organs. And OA exhibited a strong DPPH radicals scavenging activity at dose of 10, 20 and 30 mg/mL, which may contributed to alleviating cadmium-induced oxidative stress. This study revealed that OA could significantly alleviate cadmium stress via reducing cadmium-induced lipid peroxidation and SOD activity inhibition through its radicals scavenging activity.

     

Trolox and Ascorbic Acid Reduce Direct and Indirect Oxidative Stress in the IPEC-J2 Cells,an In Vitro Model for the Porcine Gastrointestinal Tract

Oxidative stress in the small intestinal epithelium is a major cause of barrier malfunction and failure to regenerate. This study presents a functional in vitro model using the porcine small intestinal epithelial cell line IPEC-J2 to examine the effects of oxidative stress and to estimate the antioxidant and regenerative potential of Trolox, ascorbic acid and glutathione monoethyl ester. Hydrogen peroxide and diethyl maleate affected the tight junction (zona occludens-1) distribution, significantly increased intracellular oxidative stress (CM-H₂DCFDA) and decreased the monolayer integrity (transepithelial electrical resistance and FD-4 permeability), viability (neutral red) and wound healing capacity (scratch assay). Trolox (2 mM) and 1 mM ascorbic acid pre-treatment significantly reduced intracellular oxidative stress, increased wound healing capacity and reduced FD-4 permeability in oxidatively stressed IPEC-J2 cell monolayers. All antioxidant pre-treatments increased transepithelial electrical resistance and viability only in diethyl maleate-treated cells. Glutathione monoethyl ester (10 mM) pre-treatment significantly decreased intracellular oxidative stress and monolayer permeability only in diethyl maleate-treated cells. These data demonstrate that the IPEC-J2 oxidative stress model is a valuable tool to screen antioxidants before validation in piglets.     

Effect of high‐dose vitamin C supplementation on growth,tissue ascorbic acid concentrations and physiological response to transportation stress in juvenile silver pomfret,Pampus argenteus

This study investigated the effect of high‐dose vitamin C supplementation on growth, tissue ascorbic acid concentrations and physiological response to transportation stress in juvenile silver pomfret, Pampus argenteus (initial average weight 6.2 ± 0.2 g). Three practical diets were formulated to contain 100 (control), 450 and 800 mg ascorbic acid/kg diet, respectively, supplied as l‐ascorbyl‐2‐polyphosphate. Each diet was fed to triplicate groups of fish in circular tanks (3 m ø, 1.5 m depth) (60 fish/tank) for 9 weeks. Growth did not change significantly with dietary vitamin C levels, although an improvement tendency with an increase in vitamin C supplementation was observed. Ascorbic acid concentrations in the liver and muscle of fish fed diets containing graded levels of vitamin C were positively correlated with dietary levels of this vitamin. Tissue ascorbic acid concentrations significantly increased with increasing vitamin C supplementation. After 9 weeks, the fish were subjected to transportation stress for 4 h to determine the influence of high vitamin C supplementation on the physiological response to this stressor. Serum cortisol, glucose and lactate levels significantly increased in stressed fish. Serum cortisol and glucose concentrations after stress were significantly higher in fish fed the control diet (7.91 μg L^?1 and 0.80 mm , respectively) than in the other groups. However, there were no significant differences in serum cortisol and glucose levels after stress between the 450 and 800 mg kg^?1 diets. No significant change could be found in serum lactate levels after stress among the different treatments. In conclusion, the dietary administration of high doses of vitamin C could reduce stress in silver pomfret and increase the survival of fish under stress conditions.     

Cellular vitamin C accumulation in the presence of copper

Under the cell-free condition, copper is known to oxidize ascorbic acid (the active form of vitamin C) and the event leads to the loss of vitamin C. However, the biological consequence of this interaction was never examined in the presence of cells. We demonstrated in intestinal epithelial cells that dehydroascorbic acid (the oxidized form of ascorbic acid), when generated from ascorbic acid in the presence of copper, can be efficiently transported into the cells and reduced back to ascorbic acid. We also observed in other types of cells the transport and intracellular reduction of dehydroascorbic acid in the presence of copper. In the presence of iron, a metal that also oxidizes ascorbic acid, we observed similar oxidation-related accumulation in intestinal cells. Other metals that do not interact with ascorbic acid had little effect on vitamin C transport. A nonmetal pro-oxidant, hydrogen peroxide, is known to oxidize ascorbic acid and we observed that the oxidation is also accompanied by an increased intracellular accumulation of vitamin C. The efficient coupling between dehydroascorbic acid transport and intracellular reduction could help to preserve the important nutrient when facing oxidative metals in the intestine.     

Augmentation of monocyte intracellular ascorbate in vitro protects cells from oxidative damage and inflammatory responses

Ascorbic acid is present as a primary antioxidant in plasma and within cells, protecting both cytosolic and membrane components of cells from oxidative damage. The effects of intracellular ascorbic acid on F(2)-isoprostanes (biomarkers of oxidative stress) and monocyte chemoattractant protein-1 (marker of inflammatory responses) production in monocytic THP-1 cells were investigated under conditions of 2,2'-Azobis(2-methylpropionamidine)dihydrochloride (AAPH) induced oxidative stress. Cells cultured under normal conditions have extremely low ascorbate levels and the intracellular ascorbate can be augmented significantly by adding ascorbate to the culture medium. While AAPH treatment reduced cell viability, increased F(2)-isoprostanes and MCP-1 production, the presence of intracellular ascorbic acid maintained high cell viability and attenuated both F(2)-isoprostanes and MCP-1 production. Measurement of intracellular ascorbic acid and its oxidised products showed that intracellular ASC was oxidised to a significantly greater extent during AAPH treatment and may be utilised to protect the cells under conditions of oxidative stress. This study demonstrates the importance of intracellular ascorbate, which may be lacking under normal cell culture conditions, under conditions of increased oxidative stress.     

Sclerotial biomass and carotenoid yield of Penicillium sp. PT95 under oxidative growth conditions and in the presence of antioxidant ascorbic acid

AIMS: To determine the effect of oxidative stress and exogenous ascorbic acid on sclerotial biomass and carotenoid yield of Penicillium sp. PT95. METHODS: In this experiment, high oxidative stress was applied by the inclusion of FeSO(4) in the growth medium and exposure to light. Low oxidative stress was applied by omitting iron from the growth medium and by incubation in the dark. Supplementation of exogenous ascorbic acid (as antioxidant) to the basal medium caused a concentration-dependent delay of sclerotial differentiation (up to 48 h), decrease of sclerotial biomass (up to 40%) and reduction of carotenoid yield (up to 91%). On the contrary, the exogenous ascorbic acid also caused a concentration-dependent decrease of lipid peroxidation in colonies of this fungus. CONCLUSIONS: Under high oxidative stress growth condition, the sclerotial biomass and carotenoid yield of PT95 strain in each plate culture reached 305 mg and 32.94 microg, which were 1.23 and 3.71 times higher, respectively, than those at low oxidative stress growth condition. These data prompted us to consider that in order to attain higher sclerotial biomass and pigment yield, the strain PT95 should be grown under high oxidative stress and in the absence of antioxidants. SIGNIFICANCE AND IMPACT OF THE STUDY: These results suggest that strain PT95 may be used for solid-state fermentation of carotenoid production under high oxidative stress growth conditions.     

Ascorbic acid reduces the frequency of iron induced micronuclei in bone marrow cells of mice

Iron is a potent oxidant that can lead to the formation of genotoxic lipid peroxides. Ascorbic acid, which enhances dietary iron absorption, has been suggested to enhance the oxidant effects of iron and to directly lead to the formation of lipid peroxides. The combined effects of dietary iron and ascorbic acid on genotoxicity were investigated by measuring the frequency of micronuclei in the bone marrow cells of C3H/He mice. In addition, liver iron concentration was measured in all treated groups. Three weeks old mice were fed diets for 3 weeks containing iron at 100 or 300 mg/kg diet in the form of FeSO₄ that were supplemented either with or without ascorbic acid (15 g/kg diet). The results of the bone marrow micronucleus test revealed that the high iron diet resulted in an increased frequency of micronucleated polychromatic erythrocytes (MnPCEs) as compared to low iron. Ascorbic acid supplementation in the low iron diet did not show any effect on incidence of MnPCEs and protected against the increased frequency of MnPCEs induced by the high iron diet. However, liver iron concentration was significantly increased only in the high iron treated and ascorbic acid supplemented group as compared to all other groups. These results demonstrate that ascorbic acid protects against the clastogenic effects of iron.     

Modulation of aconitase, metallothionein, and oxidative stress in zinc-deficient rat intestine during zinc and iron repletion

Potential interactions between zinc and iron during absorption and its functional consequences on intestinal oxidative damage and antioxidant status were studied using the zinc-deficient rat as a model. Zinc depletion produced mild-moderate iron deficiency in addition to zinc deficiency, which could be corrected by repletion with iron and zinc. The localization and intensity of both iron and zinc in the intestinal mucosa showed a pronounced decrease in the presence of the other metal, indicating negative interactions. Zinc-deficient intestine exposed to iron alone exhibited elevated peroxidative damage and compromised functional integrity, despite increased expression of ferritin. Inclusion of zinc significantly reduced the damage and improved the functional integrity, accompanied by decreased expression of ferritin. Decreased expression of ferritin in the presence of zinc was consistent with reduced aconitase activity, suggesting its modulation by zinc. Further, inclusion of iron along with zinc was associated with induction of ferritin and metallothionein in tune with the amount of iron and zinc localized in the intestinal mucosa, respectively. These results suggest that zinc and iron interact negatively with cytosolic aconitase, but prove beneficial in reducing the oxidative stress, apart from improving functional integrity and iron/zinc status.     

Antioxidant effect of diphenyl diselenide on oxidative stress caused by acute physical exercise in skeletal muscle and lungs of mice

This study was designed to examine if diphenyl diselenide (PhSe)₂, an organoselenium compound, attenuates oxidative stress caused by acute physical exercise in skeletal muscle and lungs of mice. Swiss mice were pre‐treated with (PhSe)₂ (5 mg kg^‐1 day^‐1) for 7 days. At the 7th day, the animals were submitted to acute physical exercise which consisted of continuous swimming for 20 min. The animals were euthanized 1 and 24 h after the exercise test. The levels of thiobarbituric acid reactive species (TBARS), non‐protein thiols (NPSH) and ascorbic acid and the activity of catalase (CAT) were measured in the lungs and skeletal muscle of mice. Glycogen content was determined in the skeletal muscle of mice. Parameters in plasma (urea and creatinine) were determined. The results demonstrated an increase in TBARS levels induced by acute physical exercise in the skeletal muscle and lungs of mice. Animals submitted to exercise showed an increase in non‐enzymatic antioxidant defenses (NPSH and ascorbic acid) in the skeletal muscle. In lungs of mice, activity of CAT was increased. (PhSe)₂ protected against the increase in TBARS levels and ameliorated antioxidant defenses in the skeletal muscle and lungs of mice submitted to physical exercise. These results indicate that acute physical exercise caused a tissue‐specific oxidative stress in the skeletal muscle and lungs of mice. (PhSe)₂ protected against oxidative damage induced by acute physical exercise in mice. Copyright © 2009 John Wiley & Sons, Ltd.     

Abscisic acid and oxidative stress implications in overall ferritin synthesis by African rice (Oryza glaberrima Steud.) seedlings exposed to short term iron toxicity

Iron toxicity occurs under flooded conditions such as those prevailing in lowland rice fields and is due to an excess of ferrous ions. Ferritin is a multimeric protein responsible for Fe sequestration and storage, playing a key role in Fe homeostasis. Our aim was to study the modalities of overall ferritin synthesis in different organs of young seedlings from the African rice species (Oryza glaberrima) in relation to the putative involvement of abscisic acid (ABA) and oxidative stress in signalling processes. Seedlings from a moderately resistant to iron toxicity cultivar were grown in hydroponic culture for 2 weeks and treated with 500 mg l^?1 Fe²⁺ in the presence or in the absence of 200?µM ABA, 50?µM methylviologen or 50?µM fluridone. Iron treatment increased iron and malondialdehyde concentration in all organs as well as ABA in roots and laminae. Although ferritin protein was detected in controls plants, iron treatment strongly reinforced its accumulation in sheaths and laminae after 24 h and 72 h. Ferritin mRNA was induced as early as 24 h after the beginning of the Fe-treatment in sheaths and, to a higher extent, in laminae. In the absence of iron treatment, exogenous ABA increased ferritin mRNA in laminae only but did not lead to further ferritin accumulation. Unexpectedly, it decreased ferritin mRNA levels in the sheaths of iron-treated plants and may thus have a dual influence depending on the considered organ. The inhibitor of ABA synthesis fluridone reduced endogenous ABA but did not compromise ferritin gene expression or ferritin synthesis, whatever the iron dose. Methyviologen application induced obvious oxidative damages but reduced ferritin synthesis. It is suggested that the signalling pathway leading to ferritin synthesis in the semi-aquatic African rice species may involve other components than those reported for typical terrestrial plants.     

Ascorbic acid reduces the frequency of iron induced micronuclei in bone marrow cells of mice

Iron is a potent oxidant that can lead to the formation of genotoxic lipid peroxides. Ascorbic acid, which enhances dietary iron absorption, has been suggested to enhance the oxidant effects of iron and to directly lead to the formation of lipid peroxides. The combined effects of dietary iron and ascorbic acid on genotoxicity were investigated by measuring the frequency of micronuclei in the bone marrow cells of C3H/He mice. In addition, liver iron concentration was measured in all treated groups. Three weeks old mice were fed diets for 3 weeks containing iron at 100 or 300 mg/kg diet in the form of FeSO(4) that were supplemented either with or without ascorbic acid (15 g/kg diet). The results of the bone marrow micronucleus test revealed that the high iron diet resulted in an increased frequency of micronucleated polychromatic erythrocytes (MnPCEs) as compared to low iron. Ascorbic acid supplementation in the low iron diet did not show any effect on incidence of MnPCEs and protected against the increased frequency of MnPCEs induced by the high iron diet. However, liver iron concentration was significantly increased only in the high iron treated and ascorbic acid supplemented group as compared to all other groups. These results demonstrate that ascorbic acid protects against the clastogenic effects of iron.     

A newly identified iron binding protein in duodenal mucosa of rats. Purification and characterization of mobilferrin

An iron binding protein with an approximate molecular mass of 56,000 daltons was purified to homogeneity from homogenates of rat duodenal mucosa. The protein was biochemically and immunologically distinct from transferrin and ferritin and competitively bound cobalt, copper, zinc, and lead. Each molecule bound one molecule of iron with a Kd of 9 X 10(-5). Dissociation of iron and the protein was accelerated at acid pH. Using an immunogold method, the protein was identified in the apical cytoplasm of proximal small intestinal cells and was not observed elsewhere in the intestinal mucosa and in other body organs. It was named mobilferrin from its city of origin and to differentiate it from other previously identified iron binding proteins.     

The interaction of iron and ascorbic acid with lead in the chick

Three experiments were conducted with chicks to examine the effects of dietary iron and ascorbic acid on the accumulation of lead in various organs. Lead was fed as PbCl₂, 500 or 1000 ppm Pb, iron as FeSO₄·7H₂O, 1000 ppm Fe, and ascorbic acid at 0.5%. Iron was effective in reducing the accumulation of lead in the femur and kidneys at both levels of lead. Ascorbic acid reduced the lead level in the kidneys when the concentration of lead in the diet was 500 ppm, but not at 1000 ppm. The effects of ascorbic acid on bone accumulation was variable. In two experiments the lead concentration was increased and in one it was decreased. These findings may reflect two influences of ascorbic acid found by others, namely an increase in absorption and an increase in urinary excretion. The rapid accumulation of lead in chick bones suggests that it may be an excellent experimental animal for lead studies.     

Effect of N‐acetylarginine,a metabolite accumulated in hyperargininemia,on parameters of oxidative stress in rats: protective role of vitamins and L‐NAME

In the present investigation, we initially evaluated the in vitro effect of N‐acetylarginine on thiobarbituric acid‐reactive substances (TBA‐RS), total sulfhydryl content and on the activities of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH‐Px) in the blood, kidney and liver of rats. Results showed that N‐acetylarginine, at a concentration of 5.0 μM, decreased the activity of CAT in erythrocytes, enhanced TBA‐RS in the renal cortex, decreased CAT and SOD activities in the renal medulla and decreased CAT and increased SOD and GSH‐Px activities in the liver of 60‐day‐old rats. Furthermore, we tested the influence of the antioxidants, trolox and ascorbic acid, as well as of the N^ω‐nitro‐L ‐arginine methyl ester (L‐NAME) on the effects elicited by N‐acetylarginine on the parameters tested. Antioxidants and L‐NAME prevented most of the alterations caused by N‐acetylarginine on the oxidative stress parameters evaluated. Data indicate that oxidative stress induction is probably mediated by the generation of NO and/or ONOO^? and other free radicals because L‐NAME and antioxidants prevented the effects caused by N‐acetylarginine in the blood, renal tissues and liver of rats. Our findings lend support to a potential therapeutic strategy for this condition, which may include the use of appropriate antioxidants for ameliorating the damage caused by N‐acetylarginine. Copyright © 2014 John Wiley & Sons, Ltd.     

Redox Changes in Perfusates Following Intracerebral Penetration of Microdialysis Probes

Microdialysis probe insertion into rat cerebral cortex significantly affects the levels of redox-active substances in brain extracellular fluid. Ascorbic acid levels are high immediately after probe insertion, decline rapidly, and then rise as the rat recovers from anesthesia 5–8 hours after surgery. Uric acid is at a low level for 5 hours and then rapidly increases in parallel with ascorbic acid. High ascorbic acid levels immediately after probe insertion are likely due to a shift from intracellular to extracellular fluids, whereas the delayed increase in uric acid may be due to increased enzymatic formation. After removal from the brain, hydrogen peroxide (H₂O₂) in microdialysis samples produces catalase-sensitive oxidative chemiluminescence. Microdialysis samples also produce high level catalase-resistant chemiluminescence associated with ascorbic acid levels after penetration injury. Although ascorbic acid is likely an antioxidant at concentrations estimated to be in brain extracellular fluid, it may have prooxidant effects when complexed with transition metals released into the neuronal microenvironment during traumatic brain injury.     

Aurothiomalate as Preventive and Chain‐Breaking Antioxidant in Radical Degradation of High‐Molar‐Mass Hyaluronan

The potential anti‐ or pro‐oxidative effects of a disease‐modifying antirheumatic drug, aurothiomalate, to protect high‐molar‐mass hyaluronan against radical degradation were investigated along with L ‐glutathione – tested in similar functions. Hyaluronan degradation was induced by the oxidative system Cu^II plus ascorbate known as the Weissberger's oxidative system. The time‐ and dose‐dependent changes of the dynamic viscosity of the hyaluronan solutions were studied by the method of rotational viscometry. Additionally, the antioxidative activity of aurothiomalate expressed as a radical‐scavenging capacity based on a decolorization 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) assay was inspected. At the higher concentrations tested, L ‐glutathione showed excellent scavenging of ^.OH and peroxyl‐type radicals, however, at the lowest concentration applied, its pro‐oxidative effect was revealed. The effects of aurothiomalate on hyaluronan degradation were similar to that of L ‐glutathione, however, at the lowest concentration tested, no significant pro‐oxidant effect was observed.     

Antioxidant activity of Terminalia arjuna bark extract on N-nitrosodiethylamine induced hepatocellular carcinoma in rats

Role of oxidative stress and Na⁺,K⁺-ATPase in the cytotoxicity of hexachlorocyclohexane (HCH) on Ehrlich Ascites tumor (EAT) cells has been studied. HCH caused dose dependent cell death as measured by trypan blue exclusion and lactate dehydrogenase (LDH) leakage from the cells. HCH induced oxidative stress in EAT cells which was characterized by glutathione depletion, lipid peroxidation (LPO), reactive oxygen species (ROS) production and inhibition of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT). Protective effect of antioxidants on HCH induced oxidative stress was assessed, among the antioxidants used only quercetin inhibited HCH-induced LPO and ROS production as well as cell death whereas α -tocopherol, ascorbic acid and BHA inhibited LPO but not cell death. Inhibition of membrane bound Na⁺,K⁺-ATPase was a characteristic feature of HCH cytotoxicity in EAT cells. Experimental evidence indicates that HCH-induced cell death involves oxidative stress due to ROS production and membrane perturbation in EAT cells.     

Effects of vitamin restriction and supplementation on rat intestinal epithelial cell apoptosis

Diet influences intestinal growth and function and vitamins modulate intestinal cell turnover. We have assessed the effects of chronic, moderate (50% of control) vitamin restriction and supplementation on intestinal epithelial cell (IEC) apoptosis and the relevance of this to alterations in tissue oxidative stress and antioxidant status. Feeding a vitamin-restricted diet to male, weanling WNIN rats for 20 weeks significantly increased IEC apoptosis, but only in the villi region, as evident from increased annexin V staining, M30 positivity, histological observations, DNA ladder formation, and reduced expression of Bcl-2. This was associated with elevated levels of lipid peroxides and protein carbonyls in the intestinal mucosa despite the increased activities of superoxide dismutase, catalase, and glutathione peroxidase. Consistent with the increased oxidative stress and apoptosis, structural and functional integrity of the villi were compromised as evident from the lowered ratio of villus height:crypt depth and the decreased activities of the membrane marker enzymes alkaline phosphatase and Lys-Ala dipeptidyl aminopeptidase. These changes were reversed by supplementation with a vitamin mixture or vitamin E alone, whereas riboflavin or folic acid supplementation reduced the apoptotic rates, but only partially. Further, oxidative stress was the least in vitamin E- or vitamin mixture-supplemented rats and correlated well with their IEC apoptotic rates. Increased tissue oxidative stress seems to mediate the vitamin-restriction-induced apoptosis of the IECs in rats.     

Chromium and chronic ascorbic acid depletion effects on tissue ascorbate,manganese, and14C retention from14C-ascorbate in guinea pigs

Chromium (Cr) potentiates the effects of insulin and a role for insulin in ascorbic acid transport has been reported. Therefore, the effects of Cr and ascorbate depletion on tissue ascorbic acid and¹⁴C distribution and excretion after a¹⁴C ascorbate dose were investigated in guinea pigs. As utilization of dietary Cr is affected by interaction with other minerals, tissue manganese (Mn), zinc (Zn), copper (Cu), and iron (Fe) were examined. For 20 wk, 40 weanling animals were fed either a Cr-deficient (<0.06 μg Cr/g diet, ?Cr) or a Cr-adequate (2 μg Cr from CrCl₃/g diet, +Cr) casein-based diet and were given 1 mg ascorbate/d (?C) or 10 mg ascorbate/d (+C) for 20 wk. Animals fed the Cr-depleted diet had decreased weight at 20 wk (p<0.01). Six hours before necropsy, animals were dosed by micropipette with 1.8 μCi ofl-[carboxyl-¹⁴C] ascorbic acid and placed in metabolic cages. Ascorbate supplementation increased Fe concentrations in most analyzed tissues, hepatic¹⁴C, tissue ascorbate and Mn concentration in the adrenal and testes, but decreased the concentrations of Cu in the kidney and Mn in the spleen. Liver Mn concentration was higher and kidney Mn concentration was lower in +Cr animals. Interactions between Cr and ascorbic acid affected Mn concentrations in bone and brain. These results indicate that ascorbate and Cr may affect Mn distribution. Chromium supplementation decreased plasma cortisol, brain¹⁴C and the amount of¹⁴C expired as carbon dioxide. These findings suggest that dietary Cr may affect ascorbic acid metabolism and the metabolic response to stress.