Effects of additional vitamin E and selenium supply on antioxidative defence mechanisms in the kidney of rats treated with high doses of glucocorticoid

The aim of this work was to determine the effects of dietary vitamin E and selenium (Se) on lipid peroxidation as thiobarbituric acid reactive substances (TBARS) and on the antioxidative defence mechanisms in the kidney of rats treated with high-doses of prednisolone. Two hundred and fifty adult male Wistar rats were randomly divided into five groups. The rats were fed a normal diet, but groups 3, 4, and 5 received a daily supplement in their drinking water of 20 mg vitamin E, 0.3 mg Se, and a combination of vitamin E and Se, respectively, for 30 days. For 3 days subsequently, the control group (group 1) was treated with a placebo, and the remaining four groups were injected intramuscularly with 100 mg kg(-1) body weight (bw) prednisolone. After the last administration of prednisolone, 10 rats from each group were killed at 4, 8, 12, 24, and 48 h and the activities of glutathione peroxidase (GSH-Px) and catalase (CAT) enzymes, and the levels of glutathione (GSH) and TBARS in their kidneys were measured. GSH-Px and CAT enzyme activities and GSH levels in the prednisolone treatment group (group 2) began to decrease gradually at 4 h, falling respectively to 48 and 65% of the control levels by 24 h, and recovering to the control levels at 48 h. In contrast, prednisolone administration caused an increase in TBARS in the kidneys, reaching up to twice the levels of the control group at 24 h. However, supplementation with vitamin E and Se had a preventive effect on the elevation of kidney TBARS and improved the diminished activities of the antioxidative enzymes and the levels of GSH. Therefore, the present study demonstrates the effectiveness of vitamin E and Se in reducing kidney damage in glucocorticoid-treated rats and suggests that reductions in increased TBARS due to prednisolone may be an important factor in the action of vitamin E and Se.     

Effects of dietary vitamin E and selenium on antioxidative defense mechanisms in the liver of rats treated with high doses of glucocorticoid

The aim of this work was to determine the effects of dietary intake vitamin E and selenium (Se) on lipid peroxidation as thiobarbituric acid reactive substances (TBARS) and on the antioxidative defense mechanisms in the liver of rats treated with high doses of prednisolone. Two hundred fifty adult male Wistar rats were randomly divided into five groups. The rats were fed a normal diet, but groups 3, 4, and 5 received a daily supplement in their drinking water of 20 mg vitamin E, 0.3 mg Se, and a combination of vitamin E and Se, respectively, for 30 d. For 3 d subsequently, the control group (group 1) was treated with a placebo, and the remaining four groups were injected intramuscularly with 100 mg/kg body weight (BW) prednisolone. After the last administration of prednisolone, 10 rats from each group were killed at 4, 8, 12, 24, and 48 h and the activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) enzymes and the levels of glutathione (GSH) and TBARS in their livers were measured. GSH-Px, SOD, and CAT enzyme activities and GSH levels in prednisolone-treatment group (group 2) began to decrease gradually at 4 h, falling respectively to 38%, 55%, and 40% of the control levels by 24 h, and recovering to the control levels at 48 h. In contrast, prednisolone administration caused an increase in the hepatic TBARS, reaching up to four times the levels of the control at 24 h. However, supplementation with vitamin E and Se had a preventive effect on the elevation of the hepatic TBARS and improved the diminished activities of the antioxidative enzymes and the levels of GSH. Therefore, the present study demonstrates the effectiveness of vitamin E and Se in reducing hepatic damage in glucocorticoid-treated rats and suggests that reductions in increased TBARS as a result of prednisolone may be an important factor in the action of vitamin E and Se.     

The effects of some antioxidant vitamin- and trace element-supplemented diets on activities of SOD, CAT, GSH-Px and LPO levels in chicken tissues

The effect of diets containing antioxidant vitamins and trace elements on chicken tissue activities of SOD, CAT, GSH-Px and of LPO levels was investigated. Chickens, 45 weeks of age were divided into six groups: control group, Cu group (13.2 mg Cu kg(-1) diet); Se group (0.07 mg Se kg(-l) diet); vitamin E group (70 mg DL-alpha-tocopherol acetate kg(-1) diet) and a constant level vitamin C, 200 mg kg(-1) diet); vitamin A group (240 mg retinol acetate kg(-1) diet) and vitamin C group (500 mg ascorbic acid kg(-1) diet). Significant variation of these antioxidant enzyme activities and LPO levels according to gender was demonstrated statistically. In the Cu group, CuZnSOD activity in the liver, erythrocyte, kidney and heart significantly increased by 75, 40, 12, 12% respectively (P<0.05). MnSOD activity in the heart, liver, kidney and brain of the vitamin C and in the heart of Cu group were found to be increased by approximately 15%, while in liver tissue of the Cu group it was reduced by 19% (P<0.05). GSH-Px activities in the Se, vitamin E and C groups were significantly increased, conversely LPO levels decreased (P<0.001). CAT activities in the liver and heart of the vitamin C group were significantly decreased (by 32%), but in kidney tissue only that of the Cu group was increased from 30.2 +/- 4.767 to 144.49 +/- 6.93 U mg(-1) P<0.001. The resistance to stress of the vitamin E and C groups, which had significantly increased activities of antioxidant enzymes and decreased lipid peroxide levels, were determined in 60% moisture medium at 45 degrees C.     

Effect of vitamin E and selenium on antioxidant enzymes in brain,kidney and liver of cigarette smoke-exposed mice

The present study was conducted to evaluate the protective effects of vitamin E and selenium (Se) application on alteration of antioxidant enzyme activities against cigarette smoking induced oxidative damage in brains, kidneys and liver of mice. Male mice (balb/c) were exposed to cigarette smoke and treated with Se and/or vitamin E. Glutathione transferase (GST), glutathione peroxidase (GPX), glutathione reductase (GRX), superoxide dismutase (SOD) and catalase (CAT) enzyme activities in mice brain, kidney and liver were measured spectrophotometrically. GST, GPX, GRX, SOD and CAT enzyme activities in the brains of smoke-exposed mice were found lower than the enzymes activities of control mice and Se-and vitamin E-treated mice at the end of the three and five months. Opposite to brain, enzyme activities in kidneys and livers of smoke-exposed mice were found higher than the enzymes activities of control mice and Se-and vitamin E-treated mice at the end of the three and five months. Activities of GST, GPX, GRX SOD and CAT in the livers, kidneys and brains of smoke-exposed mice were found statistically different (p < 0.01) compared to control mice and Se-and vitamin E-treated mice. Combined application of vitamin E and Se had an additive protective effect against changing enzymes activities in smoke-exposed mice livers, kidneys and brains at the end of the both application periods. These results suggest that cigarette smoke exposure enhances the oxidative stress, thereby disturbing the tissue antioxidant defense system and combined application of vitamin E and Se protects the brain, kidney and liver from oxidative damage through their antioxidant potential.     

Protective role of intraperitoneally administered vitamin E and selenium on the antioxidative defense mechanisms in rats with diabetes induced by streptozotocin

The aim of this work was to determine the protective effects of intraperitoneally administered vitamin E and selenium (as Na₂SeO₃, Se) on the lipid peroxidation as thiobarbituric acid reactive substances (TBARS) and vitamin E levels, glutathione peroxidase (GSH-Px), reduced glutathione (GSH) activities in the plasma, red blood cell (RBC), liver, and muscle of rats with streptozotocin-induced diabetes. Fifty adult male Wistar rats were used and all rats were randomly divided into five groups. The first group was used as a control and the second group as a diabetic control. A placebo was given to first and second groups by injection. The third group was intraperitoneally administered with vitamin E (20 mg over 24 h), the fourth group with Se (0.3 mg over 24 h), and the fifth group with vitamin E and Se combination (COM) (20 mg vitamin E + 0.3 mg Se over 24 h). This administration was done for 25 days and the TBARS, vitamin E, GSH-Px, GSH levels in the plasma, RBC, liver, and muscle samples were determined. The vitamin E level in the plasma and liver was significantly (p < 0.05) higher in the control than in the diabetic control group. Also, the TBARS levels in the RBC, liver, and muscle were significantly (p < 0.05) lower in the control than in the diabetic control group. However, GSH-Px and GSH activities in RBC, liver, and muscle were not statistically different between the control and the diabetic control groups. The vitamin E levels in plasma and liver (p < 0.01 and p < 0.001) and GSH-Px activities (p < 0.01, p < 0.001) in RBC were significantly higher in vitamin E, Se, and COM groups than in both control and diabetic control groups. However, the TBARS levels of RBC, muscle, and liver in vitamin E and Se administered groups were significantly (p < 0.05-p < 0.001, respectively) decreased. These results indicate that intraperitoneally administered vitamin E and Se have significant protective effects on the blood, liver, and muscle against oxidative damage of diabetes. The abstract of this study was presented in Physiological Research 48(Suppl. 1), S99 (1999).     

Protective role of intraperitoneally administrated vitamin E and selenium on the levels of total lipid,total cholesterol,and fatty acid composition of muscle and liver tissues in rats

The aim of this work was to determine the protective effects of intraperitoneally administrated vitamin E and Se on total lipid, total cholesterol, and fatty acid composition of rat liver and muscle tissues. Total lipid content of muscle tissue in Se and combination groups decreased as compared to the control group. However, the level of total lipid in the liver tissues was seen to decrease only in the combination group (P < 0.05). While the amount of total cholesterol in liver tissue was lower (P < 0.05) in the vitamin E and combination groups, the amount of total cholesterol in muscle tissue decreased (P < 0.05) in the combination group. The amount of linoleic acid in muscle tissue slightly decreased (P < 0.05), whereas the eicosenoic and eicosatrienoic acid amounts significantly increased (P < 0.01, P < 0.001) in the vitamin E group as compared to the control group. The amounts of most fatty acid decreased (P < 0.05) in the combination group. The proportions of eicosenoic, eicosatrienoic, and total polyunsaturated fatty acid (PUFA) within the total fatty acid were higher (P < 0.05) in vitamin E group, whereas these fatty acids proportions were lower (P < 0.05) in the Se group. Although the proportions of palmitic, linolenic, and total saturated fatty acids were low (P < 0.05), oleic and total unsaturated fatty acid proportions were higher (P < 0.05) in the combination group than in the control group. The amount of palmitic acid and total saturated fatty acid in liver tissue decreased (P < 0.01 and P < 0.05, respectively) in the vitamin E and combination groups. However, the amount of linoleic acid only decreased (P < 0.05) in the combination group. The amount of PUFA was slightly higher (P < 0.05) in vitamin E. The proportions of stearic acid and linoleic acid decreased (P < 0.05) both in the Se and combination groups. However, the proportions of eicosatrienoic, ω 6, and PUFA were slightly higher (P < 0.05) in the vitamin E group, but total saturated fatty acid proportion significantly decreased (P < 0.01) in both the vitamin E and combination groups. In conclusion, the level of total lipid and cholesterol in muscle and liver tissues were reduced by administrating vitamin E and Se together. Additionally, the fatty acid synthesis in the muscle and liver tissues was decreased by this process. However, it was observed that the protective effect of intraperitoneally administrated vitamin E was higher than Se on fatty acid composition in muscle and liver tissues. J. Cell. Biochem. 64:233–241. © 1997 Wiley-Liss, Inc.     

Parameters of dietary selenium and vitamin E deficiency in growing rabbits.

4 x 5 growing female rabbits (New Zealand White) with an initial live weight of 610 +/- 62 g were fed a torula yeast based semisynthetic diet low in selenium (<0.03 mg/kg diet) and containing <2 mg alpha-tocopherol per kg (group I). Group II received a vitamin E supplementation of 150 mg alpha-tocopherylacetate per kg diet, whereas for group III 0.40 mg Se as Na-selenite and for group IV both supplements were added. Selenium status and parameters of tissue damage were analyzed after 10 weeks on experiment (live weight 2,355 +/- 145 g). Selenium depletion of the Se deficient rabbits (groups I and II) was indicated by a significantly lower plasma Se content (group I: 38.3 +/- 6.23 microg Se/mL plasma, group II: 42.6 +/- 9.77, group III: 149 +/- 33.4, group IV: 126 +/- 6.45) and a significantly lower liver Se content (group I: 89.4 +/- 18.2 microg/kg fresh matter, group II: 111 +/- 26.2) as compared to the Se supplemented groups III (983 +/- 204) and IV (926 +/- 73.9). After 5 weeks on the experimental diets differences in the development of plasma glutathione peroxidase were observed. As compared to the initial status group (45.2 +/- 4.50) pGPx activity in mU/mg protein was decreased in group I (19.1 +/- 7.08), remained almost stable in the vitamin E supplemented group II (46.3 +/- 11.2) whereas an elevated enzyme activity was measured in the Se supplemented groups III (62.4 +/- 23.9) and IV (106 +/- 19.9). In the rabbit organs investigated 10 weeks of Se deficiency caused a significant loss of Se dependent cellular glutathione peroxidase activity (GPx1) of 94% (liver), 80% (kidney), 50% (heart muscle) and 60% (musculus longissimus dorsi) in comparison to Se supplemented control animals. Damage of cellular lipids and proteins in the liver was due to either Se or vitamin E deficiency. However damage was most severe under conditions of a combined Se and vitamin E deficiency. It can be concluded that the activity of plasma glutathione peroxidase is a sensitive indicator of Se deficiency in rabbits. The loss of GPx1 activity indicates the selenium depletion in various rabbit organs. Both selenium and vitamin E are essential and highly efficient antioxidants which protect rabbits against lipid and protein oxidation.     

Purification of rat kidney arginases A1 and A4 and their subcellular distribution

Arginase A1 and arginase A4 were isolated from rat kidney. Arginase A4, which is the main form of arginase in rat kidney, was obtained at a highly purified preparation; its specific activity was 1057 mumoles ornithine . min-1 . mg-1 protein. The two forms differed in subcellular localization. Form A1 was restricted to the cytosol while form A4 occurred mainly in the mitochondrial matrix. Kidney arginases A1 and A4 were found to differ in immunological properties. Kidney arginase A1, in contrast to arginase A4, precipitated with antibodies against arginase A1 from rat liver. Arginase A1 from kidney was shown to differ from arginase A1 from the liver. The two enzymes could be distinguished by double diffusion test and immunoelectrophoresis.     

Vitamin E and selenium treatment of monocrotaline induced hepatotoxicity in rats

Monocrotaline (MCT) is a hepatotoxic pyrrolizidine alkaloid that is derived from plants; exposure may occur by consumption of contaminated grains, herbal teas and medicines. MCT can cause liver damage. We investigated the antioxidant effects of selenium (Se) and vitamin E against the toxic effects of MCT. Female Wistar albino rats were divided into four groups: a control group, an MCT group, an MCT + Se group, and an MCT + vitamin E group. Liver tissues were harvested, fixed, processed to paraffin and sections were cut. Anti-von Willebrand factor (vWF) immunohistochemistry, terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL), and hematoxylin and eosin staining were performed. Serum and liver tissue glutathione (GSH), catalase (CAT), and glutathione peroxidase (GPx) levels were measured. Histopathological and TUNEL data showed significantly increased liver damage in the MCT group compared to controls. Histopathological and TUNEL staining indicated significant improvements in the MCT + vitamin E and MCT + Se groups compared to the MCT group. MCT significantly reduced the serum GSH level and GPx activity, and liver GPx activity. Biochemical data indicated a significant improvement in serum GSH level in the MCT + vitamin E group compared to the MCT group. We suggest that vitamin E and Se afford limited protection against MCT hepatotoxicity.     

Comparison of selenium level and glutathione peroxidase activity in tissues of vitamin B6-deficient rats fed sodium selenite or DL-selenomethionine

The effect of vitamin B₆ on the levels of tissue selenium (Se) and glutathione peroxidase (GSH-Px) was studied. Male Wistar 4-week-old rats were fed a vitamin B₆-Se-deficient basal diet for 2 weeks, then divided into 10 groups of five or six rats and fed their respective diets for 4 weeks. The experimental design was a 2×2×2 factorial with two levels of vitamin B₆, two forms of Se, and two levels of Se, plus two extra groups (vitamin B₆-supplemented and deficient without Se). Vitamin B₆ was 0 and 250 μg pyridoxine-HCl/100 g of diet; Se forms were Na₂SeO₃ and DL-selenomethionine; Se levels were 0.5 and 5.0 mg Se/kg of diet. Regardless of form or level of Se, vitamin B₆-deficient rats had lower body weights and organ weights than vitamin B₆-supplemented rats. At 5.0 mg Se/kg of diet, Na₂SeO₃ caused a further depression. Vitamin B₆ deficiency resulted in a higher Se level and GSH-Px activity in plasma of rats fed selenomethionine. However, Se content an GSH-Px activity in erythrocytes were significantly elevated in vitamin B₆-supplemented rats compared with vitamin B₆-deficient rats. Se levels in muscle and heart were significantly lower in vitamin B₆-deficient groups fed Na₂SeO₃ than in vitamin B₆-supplemented groups. Vitamin B₆-deficient rats fed selenomethionine had higher Se levels in muscle, heart, spleen, liver, and kidneys than vitamin B₆-supplemented rats. Activity of GSH-Px in muscle, heart, and spleen was significantly lower in vitamin B₆-deficient groups than in vitamin B₆-supplemented groups, regardless of form of Se. A significant decrease of GSH-Px in liver was observed in vitamin B₆-deficient rats fed selenomethionine compared with vitamin B₆-supplemented rats, whereas no significant decrease was observed in those fed Na₂SeO₃. These results suggest that vitamin B₆ is involved in the distribution and transportation of Se in body and the metabolism of selenomethionine in liver.     

Protective role of intraperitoneally administered vitamin E and selenium in rats anesthetized with enflurane

The aim of this investigation was to determine levels of liver vitamins A and E and blood biochemical and hematological parameters in the enflurane anesthesia of rats. Fifty adult male Wistar rats were used in this study. All rats were randomly divided into five groups. The first and second groups were used as the control and anesthesia control groups, respectively, and only the placebo was intraperitoneally injected. The third group was intraperitoneally administered with vitamin E (dl/-α-tocopheryl acetate, 100 mg/kg body weight), the fourth group with Se (Na₂SeO₃ 1.5 mg/kg body weight), and the fifth group with vitamin E and Se (dl-α-tocopheryl acetate, 100 mg/kg body weight + Na₂SeO₃ 1.5 mg/kg body weight). This administration was done for three times with overday intervals and the second, third, forth, and fifth group rats were taken to enflurane anesthetise for 2 h. The liver vitamin E level was slightly lower in the anesthesia control group than in control group. However, the liver vitamin E content was significantly (p < 0.05 andp < 0.01) increased in vitamin E, Se, and combination groups, whereas the vitamin A level in liver was not statistically different. In general, plasma levels of alanine aminotransferase, creatin kinase, total bilirubin, urea, red blood cell counts, packet cell volume, and hemoglobulin values were significantly (p < 0.05 andp < 0.001) increased during the anesthesia and returned to near control values after the vitamin E plus selenium injection. However, administration of vitamin E had less effect on the hematological and biochemical parameters compared to that of selenium and their combination with vitamin E. However, the white blood cell count and levels of alkaline phosphatase, aspartate aminotransferase, total cholesterol, triglycerides, total protein, and creatinine were not statistically influenced by the anesthesia. In conclusion, we observed that plasma levels of some enzymes and metabolites were significantly increased in the enflurane anesthesia of rats, whereas the liver vitamin E levels were slightly decreased. Therefore, we observed that vitamin E and selenium have a protective effect against anesthesia complication, but the effect of selenium appears to be much greater than the vitamin E.     

The role of dietary copper,manganese, selenium,and vitamin E in lipid peroxidation in tissues of the rat

The role of dietary Cu and Mn in maintaining tissue integrity, through the effects of these metals on activity of the superoxide dismutase (SOD) enzyme, and their interactions in peroxidative pathways involving Se and vitamin E was investigated. Weanling rats were fed diets deficient in Mn, Cu, Se, and/or vitamin E for 35 days, in a factorial experimental design. Dietary effects on peroxidation, measured in mitochondrial fractions prepared from liver and heart tissue, were compared with changes in the activities of glutathione peroxidase and the Cu and MnSOD enzymes. Decreased heart MnSOD and CuSOD activities, resulting from dietary Mn and Cu deficiencies, were both associated with increased peroxidation. Adequate Se (and glutathione peroxidase activity) prevented the peroxidation associated with either of these deficiencies, but was ineffective with a combined Cu−Mn deficiency. These effects of Se were only observed in tissue lacking glutathione transferase activity. Effects of Cu, Mn, and Se on peroxidation appeared to be present at both levels of vitamin E, although in both tissues, vitamin E deficiency greatly increased the overall peroxidation. Comparison of these in vitro peroxidation results with the deficiency associated lesions observed in vivo indicates that changes in SOD activities and peroxidation pathways may be the dominant cause of these lesions in only some cases. In others, the roles of Cu and Mn in different metabolic pathways appear to be of greater importance.     

Effects of intraperitoneally injected selenium and vitamin E in rats anesthetized with halothane.

Halothane, commonly used for anesthetizing humans and animals, is one of the most important volatile anesthetics and may cause the formation of free radicals during its biotransformation. Free radicals may lead to degeneration of liver cells. Vitamin E and glutathione peroxidase (GSH-Px) containing selenium are two natural antioxidants, and these may protect the cellular lipid and lipoproteins against oxidative damage caused by free radicals. Therefore, the purposes of the present study were to investigate the probable protective effects of intraperitoneally administered Se and vitamin E on liver enzymes and to determine some other hematological parameters in the halothane anesthesia of rats. All rats were randomly divided into five groups. The first group was used as a control, and physiological saline (0.9%) was intraperitoneally injected into these animals as a placebo. The second group was used as an anesthesia control group and was only anesthetized with halothane for two hours. The third group received intraperitoneally administered Se (Na2SeO3, 0.3 mg/200 g body weight), the fourth group vitamin E (dl-alpha-tocopheryl acetate, 100 mg/kg body weight), and the fifth group a Se plus vitamin E combination (Na2SeO3, 0.3 mg/200 g body weight + dl-alpha-tocopheryl acetate, 100 mg/kg body weight). The activities of aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase, triglycerides, erythrocyte counts, the packet-cell volume, hemoglobin concentrations and neutrophyle rates significantly increased (p < 0.05 to p < 0.01) after halothane anesthesia and returned to near control levels after Se, vitamin E and Se plus vitamin E injections. The values of cholesterol, total protein, white blood cell counts and lymphocyte rates significantly decreased (p < 0.05 to p < 0.01) in the anesthesia control group. However, the levels of albumin, total bilirubin, creatinine, the mean corpuscular volume, the mean corpuscular hemoglobin, and the mean corpuscular hemoglobin concentration were not statistically influenced. In conclusion, we have determined that halothane anesthesia affected some liver enzymes and some other biochemical and hematological parameters. Se, vitamin E and their combination may prevent the increase of liver enzymes after halothane anesthesia. Based upon these results, Se and vitamin E may play an important role in the indication of hepatic cellular injury produced by halothane.     

Effect of vitamin E and selenium supplementation of cockerel diets on glutathione peroxidase activity and lipid peroxidation susceptibility in sperm, testes, and liver

The phospholipids of avian spermatozoa are characterized by high proportions of arachidonic (20:4n-6) and docosatetraenoic (22:4n-6) fatty acids and are therefore sensitive to lipid peroxidation. α-Tocopherol and glutathione peroxidase [GSH-Px] are believed to be the primary components of the antioxidant system of the spermatozoa. The present study evaluates the effect of vitamin E and vitamin E plus Se supplementation of the cockerel diet on GSH-Px activity, vitamin E accumulation, and lipid peroxidation in the spermatozoa, testes, and liver. At the beginning of the experiment 75 Rhode Island Red cockerels were divided into five groups, kept in individual cages, and fed a wheat-barley-based ration balanced in all nutrients. Supplements fed to the different groups were as follows: vitamin E, 0, 20, 200, 20, and 200 mg/kg to groups 1–5, respectively, with groups 4 and 5 also receiving 0. 3 mg Se/kg. The vitamin E supplementation produced increased levels of α-tocopherol in semen, testes, and liver. The inclusion of the Se into the cock diet had a significant (P < 0.01) stimulating effect on GSH-Px activity in seminal plasma, spermatozoa, testes, and liver. The increased vitamin E concentration in the spermatozoa was associated with a reduction in their susceptibility to lipid peroxidation. Similarly, the increased GSH-Px activity provided enhanced protection against lipid peroxidation.     

Influence of dietary selenium and vitamin E on the levels of fatty acids in brain and liver tissues of lambs

In this study, the effects of dietary vitamin E, selenium, and their combination on the levels of fatty acid composition of the brain and liver tissues were examined. In brain tissue, the amounts of most fatty acids increased in vitamin E, combination and selenium groups compared with control group values. While the proportions of myristic, pentadecanoic, palmitic, linoleic, and total saturated fatty acids were decreased in vitamin E, Se and combination groups, eicosapentaenoic, total unsaturated and MUFA were increased in the same groups. In addition, the proportions arachidonic, eicosapentaenoic, total unsaturated, ω6 and MUFA in the combination group were higher than in the control group. In liver tissue, the amounts of myristic, pentadecanoic, palmitic, eicosedienoic, eicosapentaenoic, docosahexaenoic, ω3 and PUFA were higher in the combination group than in the control group. Also the proportions of eicosapentaenoic, docosahexaenoic acids in supplemented groups were higher than those in the control group. We conclude that dietary vitamin E and selenium have an influence on the levels of fatty acids in the brain and liver. Copyright © 1999 John Wiley & Sons, Ltd.     

Effects of antioxidant vitamins A, C, E and trace elements Cu, Se on CuZn SOD, GSH-Px, CAT and LPO levels in chicken erythrocytes

The biologically damaging effects of reactive oxygen species are controlled in vivo by a wide spectrum of antioxidant defence mechanisms. Dietary constituents of antioxidant vitamins and trace elements may play an important role in protecting against oxidant damage. The effects of supplementation of vitamins A, C, E and trace elements Cu and Se on the activities of antioxidant enzymes and lipid peroxide levels in chicken erythrocytes were investigated depend on the time. CuZnSOD activity and plasma Cu levels in the Cu group were increased by 39 and 37 per cent respectively. CuZnSOD activity in vitamin C groups was also increased by 20 per cent. The GSH-Px activity in Se, Se+E and Se+Cu groups was raised by 35, 46 and 69 per cent respectively. Also, the GSH-Px activity in the vitamin C group was increased by 33 per cent. Catalase activity in all of these groups was not significantly different when compared with controls (p<0.01). The maximum decrease in LPO levels of 42 per cent was obtained for the Se+E group.     

Effect of increasing selenite concentrations, vitamin E supplementation and different fetal calf serum content on GPx1 activity in primary cultured rabbit hepatocytes

Primary rabbit hepatocytes from 6 week old female New Zealand White rabbits (3.0 x 10(6) viable hepatocytes per treatment) were incubated for 24 h or 48 h with two basic variants of the selenium and vitamin E free DMEM/F12-HAM nutrition medium containing 2.5% or 10% fetal calf serum (FCS). Selenium and vitamin E concentrations of the media were varied by the addition of 0, 10, 50 and 100 ng Se/mL medium as sodium selenite and 100 microg alpha-tocopheryl acetate/mL. Lactic dehydrogenase (LDH) leakage of the hepatocytes was not influenced by the various selenium concentrations of the media, whereas vitamin E addition significantly inhibited LDH release. The activity of cellular glutathione peroxidase (GPx1) was markedly induced by increasing the selenium supplementation of the culture media. Vitamin E supply further enhanced GPx1 induction. In hepatocytes cultivated at the lower serum concentration (2.5% FCS), increasing the selenite concentration of the media raised GPx1 and reduced the intracellular levels of the reduced tripeptide glutathione (GSH). No vectored relation between the selenium concentration of the media and the activity of superoxide dismutase (SOD) could be observed. After both incubation periods (24 h and 48 h) SOD activity was significantly higher in the cytosol of hepatocytes grown in media containing 10% FCS as compared to cells incubated at the 2.5% FCS level. Furthermore, SOD activity was reduced by the addition of vitamin E to the media. In conclusion the results indicate an effective metabolism of rabbit hepatocytes for selenite even in amounts as low as nanograms. A general cytoprotective role for vitamin E can be shown by its ability to decrease LDH leakage and by the reduction of SOD activity.     

Effects of nicotine and vitamin E on 6-phosphogluconate dehydrogenase activity in some rat tissues in vivo and in vitro

The aim of this study was to investigate whether nicotine affects 6-phosphogluconate dehydrogenase (6PGD) enzyme activity in some rat tissues, and to see the modulatory effects of vitamin E on this effect in vivo. In addition, the effects of nicotine and vitamin E on 6PGD activity were also tested in vitro. The groups were: nicotine [0.5 mg/kg/day, intraperitoneal (i.p.)]; nicotine + vitamin E [75 mg/kg/day, intragastric (i.g.)]; and control group (receiving only vehicles). There were eight rats per group and supplementation period was 3 weeks. The results of in vivo study showed that nicotine activated the muscle, lungs, and testicular 6PGD enzyme activity but had no effect on heart and liver 6PGD activity. Also, nicotine + vitamin E activated the muscle, testicle, and liver 6PGD enzyme activity, while this combination had no effect on heart, and lungs in vivo. When nicotine is administered with vitamin E the increase in 6PGD enzyme activity in muscle and testicles were lower. On the other hand the increase in 6PGD enzyme activity was eliminated by vitamin E in lungs, while 6PGD enzyme activity was increased by vitamin E, which was not affected by nicotine only. In vitro results correlated well with in vivo experimental results. Our results suggest that vitamin E may favourably increase 6PGD enzyme activity in liver in nicotine treated rats, while it has negligible effects on this enzyme activity in other tissues.     

Enhanced testicular antioxidant capacity in streptozotocin-induced diabetic rats: protective role of vitamins C and E and selenium

Diabetes mellitus is associated with diabetic impairment of testicular function, ultimately leading to reduced fertility. Its etiology may involve oxidative damage by reactive oxygen substances, and protection against this damage can be offered by antioxidant supplementation. The aim of this study was to investigate the effects of intraperitoneal administration of vitamin C and E, selenium (Se), and vitamin E plus Se (COM) on concentrations of lipid peroxide (as malondialdehyde; MDA), reduced glutathione (GSH), and vitamin E concentrations and glutathione peroxidase (GSH-Px) activity in the testes of rats with diabetes induced by streptozotocin (STZ). Sixty groups were used (10 animals each) and these animals were initially allocated to two groups: control group and diabetic group. The diabetic group was subdivided into five groups as follows: diabetic control (DC), vitamin E, Se, COM, and vitamin C. Animals in the DC group and vitamin C, vitamin E, Se, and COM groups were made diabetic by the injection of STZ on 4 d after an injection of vitamins C and E, Se, and COM. Those vitamins and Se were also administered for 21 consecutive days. The MDA, vitamin E, GSH levels, and GSH-Px activities in testes were determined. Although the vitamin E concentration was higher in the control than in the DC group, the MDA levels were found to be lower in the control than in the DC group. The MDA levels in the testes samples of vitamin C, vitamin E, Se, and COM groups were lower than the DC group. However, GSH-Px activity and GSH levels in the testes were not significantly different between the control and DC groups. Vitamin E concentrations in the vitamin C, vitamin E, Se, and COM groups and GSH levels and GSH-Px activities in the Se, COM, and vitamin C groups were higher than either the control or DC group. The results indicate that reactive oxygen substances may be involved in possible testicular complications in diabetes of rats. Administration of vitamins C and E and Se reduced the testicular lipid peroxidation; these vitamins and Se had significant protective effects on testes of rats against oxidative damage in diabetes.     

Rat Mammary Arginase: Isolation and Characterization

The extrahepatic arginase, AII, from rat mammary gland was isolated and its properties investigated and compared with those of the hepatic arginase, AI. Mammary arginase activity increased 300% at mid-lactation, an increase unaccompanied by an increase in liver arginase activity. Mammary gland contained two isozymes, separable by ion exchange chromatography. The major form, AII, was purified 103-fold and antisera were raised against it. A 1300-fold purification was achieved temporarily but the enzyme was unstable. Arginase AII was kinetically similar to AI: both had pH optima of 10 and K_ms for L-arginine of 12-14 mM. Arginase AII differed from AI in having a near-neutral pI and a slightly larger subunit size (39,800 Da compared to 38,900 Da by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)). Solution immunoprecipitation studies revealed that virtually all of the arginase present in liver was type AI, whereas kidney and mammary gland contained both isozymes. Western immunoblotting showed that the amount of immunoreactive mammary arginase AII protein increased at mid-lactation in parallel with the increase in activity. This suggests that the elevated arginase activity is due to de novo protein synthesis and/or reduced protein degradation, rather than activation of arginase.