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This study is aimed at investigating the inhibitory effect of cadmium ion on glutathione reductase activity of rabbit brain
and liver and the relationship of this effect with dietary selenium. For this purpose, one group of New Zealand rabbits were
fed a selenium-deficient diet, another group was fed a selenium-rich diet, and the control group was fed a normal diet. The
brain and liver tissues of these groups were investigated for the in vitro inhibitory effects of Cd2+ on glutathione reductase activity. For liver, the percentage inhibition of glutathione reductase by 40 nmol/mg protein of
Cd2+ was similar for selenium-deficient and control groups, but significantly lower in the selenium-rich group. For brain tissues,
there was no difference with respect to cadmium inhibition of glutathione reductase in all three groups. 相似文献
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A comparative study on effect of dietary selenium and vitamin E on some antioxidant enzyme activities of liver and brain tissues 总被引:5,自引:0,他引:5
Since selenium and vitamin E have been increasingly recognized as an essential element in biology and medicine, current research
activities in the field of human medicine and nutrition are devoted to the possibilities of using these antioxidants for the
prevention or treatment of many diseases. The present study was aimed at investigating and comparing the effects of dietary
antioxidants on glutathione reductase and glutathione peroxidase activities as well as free and protein-bound sulfhydryl contents
of rat liver and brain tissues. For 12–14 wk, both sex of weanling rats were fed a standardized selenium-deficient and vitamin
E-deficient diet, a selenium-excess diet, or a control diet. It is observed that glutathione reductase and glutathione peroxidase
activities of both tissues of the rats fed with a selenium-deficient or excess diet were significantly lower than the values
of the control group. It is also shown that free and bound sulfhydryl concentrations of these tissues of both experimental
groups were significantly lower than the control group. The percentage of glutathione reductase and glutathione peroxidase
activities of the deficient group with respect to the control were 50% and 47% in liver and 66% and 61% in the brain, respectively;
while these values in excess group were 51% and 69% in liver and 55% and 80% in brain, respectively. Free sulfhydryl contents
of the tissues in both experimental groups showed a parallel decrease. Furthermore, the decrease in protein-bound sulfhydryl
values of brain tissues were more pronounced than the values found for liver. It seems that not only liver but also the brain
is an important target organ to the alteration in antioxidant system through either a deficiency of both selenium and vitamin
E or an excess of selenium alone in the diet. 相似文献
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Sheep brain glutathione reductase was purified about 11,000-fold with an overall yield of 40%. The method included ammonium sulphate fractionation, heat denaturation, 2',5'-ADP Sepharose 4B and Sephadex G-200 chromatography steps. Specific activity at the final step was 193 IU/mg. The Mr of the enzyme was found to be 116,000 by gel filtration chromatography. On SDS-PAGE, two identical subunits of Mr 64,000 were obtained. From the spectral data, about 2 mol FAD per mol of enzyme were calculated. 相似文献
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NM Kouyoumdzian NL Rukavina Mikusic G Cao MR Choi SL Della Penna BE Fernández 《Biotechnic & histochemistry》2016,91(8):510-521
We studied the effects of tempol, an oxygen radical scavenger, on hydrosaline balance in rats with acute sodium overload. Male rats with free access to water were injected with isotonic (control group) or hypertonic saline solution (0.80 mol/l NaCl) either alone (Na group) or with tempol (Na-T group). Hydrosaline balance was determined during a 90 min experimental period. Protein expressions of aquaporin 1 (AQP1), aquaporin 2 (AQP2), angiotensin II (Ang II) and endothelial nitric oxide synthase (eNOS) were measured in renal tissue. Water intake, creatinine clearance, diuresis and natriuresis increased in the Na group. Under conditions of sodium overload, tempol increased plasma sodium and protein levels and increased diuresis, natriuresis and sodium excretion. Tempol also decreased water intake without affecting creatinine clearance. AQP1 and eNOS were increased and Ang II decreased in the renal cortex of the Na group, whereas AQP2 was increased in the renal medulla. Nonglycosylated AQP1 and eNOS were increased further in the renal cortex of the Na-T group, whereas AQP2 was decreased in the renal medulla and was localized mainly in the cell membrane. Moreover, p47-phox immunostaining was increased in the hypothalamus of Na group, and this increase was prevented by tempol. Our findings suggest that tempol causes hypernatremia after acute sodium overload by inhibiting the thirst mechanism and facilitating diuresis, despite increasing renal eNOS expression and natriuresis. 相似文献
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N. Leyla Acan 《Journal of enzyme inhibition and medicinal chemistry》2013,28(5):457-464
Human erythrocyte pyruvate kinase was modified with bromopyruvate and the kinetic behavior of the modified enzyme was investigated. When the enzyme was modified with bromopyruvate in the absence of adenosine-5′s-diphosphate, phospho-enolpyruvate or fructose-1,6-diphosphate the inactivation followed a pseudo first-order kinetics. The inactivation rate constant, ks, was 1.84 × 0.15 min?1. Kd of the bromopyruvate-enzyme complex was 0.14 × 0.03 mM.The presence of adenosine-5′-diphosphate, phosphoenolpyruvate or fructose-1,6-diphosphate in the modification medium or the presence of fructose-1,6-diphosphate in the assay medium resulted in deviation of the inactivation kinetics from pseudo first-order. Phosphoenolpyruvate was better than adenosine-5′-diphosphate for protection against bromopyruvate modification whereas fructose-1,6-diphosphate was ineffective. The modified enzyme showed negative cooperativity in the presence of fructose-1,6-diphosphate whereas in the absence of it no activity was detected. 相似文献
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Can B Ulusu NN Kilinç K Leyla Acan N Saran Y Turan B 《Biological trace element research》2005,105(1-3):135-150
We have shown that a single dose of streptozotocin (STZ) (50 mg/kg body weight) injected into rats caused significant changes in some antioxidant enzyme activities, such as glutathione peroxidase, glutathione reductase, glutathione-S-transferase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase activities, and acid-soluble sulfhydryl levels of the liver tissue with respect to the control rats. Furthermore, these alterations in the activities of the antioxidant enzymes were accompanied by significant changes in the ultrastructure of the liver tissue; mainly intercellular biliary canaliculi were distended and contained stagnant bile, swollen mitochondria in hepatocytes and disoriented and disintegrating cristae, dilatation of the rough endoplasmic reticulum (rER) with detachment of ribosomes, and dissociation of polysomes. Both diabetic and normal rats were treated with sodium selenite (5 micromol/kg/d, intra peritoneally) for 4 wk following 1 wk of diabetes induction. This treatment of diabetic rats improved significantly diabetes-induced alterations in liver antioxidant enzymes. Moreover, treating of diabetic rats with sodium selenite prevented primarily the variation in staining quality of hepatocytes nuclei, increased density and eosinophilia of the cytoplasm, focal sinusoidal dilatation and congestion, and increased numbers of mitochondria with different size and shape. In summary, treatment of diabetic rats with sodium selenite has beneficial effects on both antioxidant system and the ultrastructure of the liver tissue. These findings suggest that diabetes-induced oxidative stress can be responsible for the development of diabetic complications and antioxidant treatment can protect the target organs against diabetes. 相似文献
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