Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.11.1.9 (glutathione peroxidase)
 22,002 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of glutathione (GSH) synthesis modulators - L-buthionine sulfoximine (BSO), N-acetyl cysteine (NAC) and D-penicillamine (DPA) - on the susceptibility of rat CNS to O2 toxicity was investigated. The animals were given 5% sucrose or 40 mM solutions of BSO, NAC or DPA in 5% sucrose as drinking water for one week and sacrificed prior to or after exposure to 4.5 ATA O2. The GSH content in brain, liver, lung and blood, and the activity of glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-R), glucose-6-phosphate dehydrogenase (G-6-PD) and superoxide dismutase (SOD) in brain and lungs were measured. The brain GSH content and the enzyme activities were not changed by any of the drugs. BSO decreased the GSH content in all the other tissues; NAC and DPA treatments increased the GSH content in lungs, blood and/or liver. The CNS toxicity threshold as measured by the time of appearance of first electrical discharge (FED) on ECoG recording was not changed by NAC or DPA, but BSO brought about a significant delay in FED time. It is suggested that increased extracerebral GSH levels do not protect against CNS oxygen toxicity, and that BSO provides some protection, probably via a glutathione-independent mechanism.
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PMID:Effect of N-acetyl-cysteine, D-penicillamine and buthionine sulfoximine on glutathione levels and CNS oxygen toxicity in rats. 230 9

As many as 160 patients with acute virus hepatitis B (AVHB) were examined over time. Spectroscopy was used to study the activity of glucose-6-phosphate dehydrogenase (G-6-PDH), glutathione peroxidase-1 (GP1), glutathione peroxidase-2 (GP2), glutathione reductase (GR), glutathione transferase (GT) and to measure the concentration of reduced glutathione (GSH) in the blood serum and in red blood cells. Within the first days of the icteric period, the activity of all the enzymes rose, followed by reduction of the activity of G-6-PDH, GP1, GP2, GR and the concentration of GSH at the height of the disease. The GT activity remained high throughout the entire disease period.
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PMID:[The functioning of the glutathione system in patients with acute viral hepatitis B]. 233 29

Adult worms of Ancylostoma ceylanicum and Nippostronglyus brasiliensis were found to possess an active system for the detoxification of reactive oxygen intermediates. Xanthine oxidase, which is known to produce superoxide anion, was detected in both the nematode parasites in significant activities. Superoxide anion, thus produced, may quickly be eliminated by superoxide dismutase. Both parasites also exhibited the presence of catalase, peroxidase, and glutathione peroxidase for efficient removal of hydrogen peroxide. Glutathione reductase and glucose-6-phosphate dehydrogenase were, however, detected in low levels of activities. Endowment of A. ceylanicum and N. brasiliensis with these antioxidant enzymes, therefore, enables them to evade the host's effector mechanism for their survival. Superoxide dismutase of both these nematodes showed marked inhibition by KCN and, hence, the enzyme appears to be of copper-zinc type.
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PMID:Reactive oxygen intermediates metabolizing enzymes in Ancylostoma ceylanicum and Nippostrongylus brasiliensis. 234 Oct 58

The activity of anti-oxidant enzymes in the brains of newborn piglets were studied under the condition of ischemic hypoxia followed by reperfusion. The activity of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glucose-6-phosphate dehydrogenase, was determined in the brain tissue of control animals and animals exposed to 60 min of hypoxia followed by 30 min of normoxia. The results showed that the activities of these enzymes were not significantly affected by hypoxia and subsequent reperfusion, suggesting that under these conditions the anti-oxidant system is not a target for, nor is its inhibition a cause of, cellular damage. It is proposed that the anti-oxidant enzyme system in the brain is non-responsive to and may not play a role during hypoxia/ischemia and subsequent reperfusion.
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PMID:Anti-oxidant enzymes in the brain of newborn piglets during ischemia followed by reperfusion. 235 95

Collagen stimulation of blood platelets resulted in significant increases in malondialdehyde (MDA) formation and activity of glucose-6-phosphate dehydrogenase (G6PDH) and a decrease in catalase and glutathione peroxidase (GPx). Retinoic acid (RA) pretreatment did not show any appreciable changes except for a decrease in G6PDH activity as compared with collagen alone. RA pretreatment of human blood platelets resulted in an increase in the activities of catalase and GPx, two important radical scavenging enzymes, with significant decrease in MDA formation when compared with ADP alone. It is suggested that RA has a significant effect on the antioxidant defence system in ADP stimulated platelets but not in the collagen stimulated platelets.
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PMID:Effect of retinoic acid on adenosine diphosphate and collagen-induced alterations in enzymes of GSH-linked antioxidant defence system of human blood platelets in vitro. 240 28

The administration of single i.p. doses of lindane (20, 40, 60 and 80 mg/kg) to rats produced a progressive increase in the liver microsomal content of cytochrome P-450 and in the rate of superoxide anion generation, as measured by adrenochrome formation. A dose-dependent increase in lipid peroxidation of liver homogenates, assessed by measuring thiobarbituric acid reactants, was also found. Lindane treatment did not alter the activity of liver glucose-6-phosphate dehydrogenase, glutathione reductase or glutathione peroxidase, while that of superoxide dismutase and catalase was significantly reduced. These changes were accompanied by a progressive liver steatosis. The collected metabolic data were interpreted in terms of a causal relationship between an increase in superoxide radical generation, secondary to cytochrome P-450 induction and a resulting increase in lipid peroxidation. The decrease in superoxide dismutase and catalase activities is likely to contribute to the increased levels of lipid peroxidation in view of their antioxidant properties.
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PMID:Dose-dependent study of the effects of acute lindane administration on rat liver superoxide anion production, antioxidant enzyme activities and lipid peroxidation. 242 6

Dietary fat-type and copper (Cu) deficiency have been independently identified as potentially important factors in the etiology of ischemic heart disease (IHD); a disease that has been linked to inflammation and oxygen free radical (OFR) mediated damage. Group (n = 6) of male, weanling, Wistar rats were provided ad libitum with deionized water and control or low Cu diets containing (200 g/kg) either saturated or polyunsaturated fatty acids (SFA or PUFA, respectively) for 56 d. Measurement of several indices of Cu status indicated that both groups fed the low Cu diets were Cu-deficient. SFA consumption resulted in significantly increased hepatic Cu (p less than 0.001) and iron (Fe) (p less than 0.001) concentrations and xanthine oxidase activity (p less than 0.05) and significantly decreased hepatic glucose-6-phosphate dehydrogenase activity (p less than 0.001). Although Cu deficiency resulted in significantly decreased hepatic copper-zinc superoxide dismutase (CuZnSOD) activity (p less than 0.01), no significant effect on the activities of the other hepatic antioxidant enzymes, manganese superoxide dismutase, catalase, and glutathione peroxidase, or glutathione reductase, were observed. Cu deficiency also resulted in significantly decreased hepatic Cu levels (p less than 0.001) and cytochrome c oxidase activity (p less than 0.01). No significant difference in hepatic thiobarbituric acid reactive substances (TBARS), a measure of lipid peroxidation, was found between groups consuming SFA or PUFA, but both Cu-deficient groups exhibited significantly increased hepatic TBARS (p less than 0.001), compared to controls. This was probably owing to the significantly decreased hepatic CuZnSOD activity observed in the Cu-deficient, compared to control animals.
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PMID:Dietary saturated or polyunsaturated fat and copper deficiency in the rat. 248 34

Genetic deficiencies of glucose-6-phosphate dehydrogenase (G6PD) and NADPH predispose affected erythrocytes to destruction from peroxides. Conversely, genetic deficiencies of catalase do not predispose affected erythrocytes to peroxide-induced destruction. These observations have served to strengthen the assumption that the NADPH/glutathione/glutathione peroxidase pathway is the principal means for disposal of H2O2 in human erythrocytes. Recently, however, mammalian catalase was found to have tightly bound NADPH and to require NADPH for the prevention and reversal of inactivation by its toxic substrate (H2O2). Since both catalase and the glutathione pathway are dependent on NADPH for function, this finding raises the possibility that both mechanisms destroy H2O2 in human erythrocytes. A comparison of normal and acatalasemic erythrocytes in the present study indicated that catalase accounts for more than half of the destruction of H2O2 when H2O2 is generated at a rate comparable to that which leads to hemolysis in G6PD- deficient erythrocytes.
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PMID:Catalase and glutathione peroxidase are equally active in detoxification of hydrogen peroxide in human erythrocytes. 249 51

Rats injected with interleukin-1 (10 micrograms) and tumor necrosis factor (10 micrograms) and then exposed continuously to hyperoxia (greater than 99% O2, 1 atm) survived longer, had increased lung reduced/oxidized glutathione ratios, smaller pleural effusions, less pulmonary hypertension and improved arterial blood gases. The percentage of animals surviving for 72 hours in hyperoxia increased from 8% to 94%. Although relatively small increases in glutathione redox cycle enzymes occurred four and sixteen hours following cytokine injection, dramatic increases in all major antioxidant enzymes including superoxide dismutase, glucose-6-phosphate dehydrogenase, glutathione reductase, glutathione peroxidase, and catalase had occurred following 72 hours of exposure to hyperoxia. The protective effect of IL-1 + TNF against lethal pulmonary O2 toxicity could be partially inhibited by pre-injection of lysine acetylsalicylate or, less effectively, of ibuprofen. Recent studies have suggested that both IL-1 and TNF can induce manganese (mitochondrial) superoxide dismutase mRNA and protein synthesis in a variety of cell types. Preliminary studies suggest that IL-1 alone, in ample dosage, can provide protection against lethal pulmonary O2 toxicity. Future studies should be directed toward identification of acute phase changes in lung antioxidant enzymes, surfactant proteins and/or lipid components, enzymes needed for synthesis of surfactant phospholipids, and/or other protective proteins. Additional work also needs to be done in identifying the lung cell types in which early enzyme induction occurs. These studies should provide a better understanding of mechanisms whereby protection against pulmonary O2 toxicity can occur. An understanding of the molecular mechanisms inducing protective proteins should lead to more precise pharmacologic control of these processes.
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PMID:Protection against pulmonary oxygen toxicity by interleukin-1 and tumor necrosis factor: role of antioxidant enzymes and effect of cyclooxygenase inhibitors. 251 82

1. A number of dietary sugars are known to mediate the effects of copper deficiency. The effects of lactose (compared with sucrose) and a dietary Cu deficiency on hepatic and cardiac antioxidant enzyme activities and tissue mineral element status were investigated in the rat. 2. Groups (n 6) of male weanling Wistar rats were provided ad lib. with deionized water and diets containing sucrose (580 g/kg) or sucrose and lactose (387 g/kg and 193 g/kg respectively) with either control (12.0 mg/kg) or deficient (1.5 mg/kg) quantities of Cu for 77 d. 3. Animals consuming the low-Cu diets exhibited significantly decreased tissue Cu levels (P less than 0.01), hepatic and cardiac cytochrome c oxidase (EC 1.9.3.1, CCO) activities (P less than 0.01 and P less than 0.001 respectively) and hepatic Cu-zinc superoxide dismutase (EC 1.15.1.1, CuZnSOD) activity (P less than 0.05). The low-Cu diets also significantly decreased cardiac manganese superoxide dismutase (EC 1.15.1.1, MnSOD), catalase (EC 1.11.1.6) and glutathione peroxidase (EC 1.11.1.9, GSH-Px) activities (P less than 0.01, P less than 0.05 and P less than 0.001 respectively). 4. Hepatic Mn was significantly increased in both lactose-fed (P less than 0.001) and Cu-deficient (P less than 0.01) animals. These increases were unrelated to hepatic MnSOD activity. Cardiac Zn was significantly (P less than 0.01) increased in Cu-deficient animals. 5. Lactose feeding resulted in significantly increased cardiac CCO activity (P less than 0.001) but significantly decreased hepatic CuZnSOD (P less than 0.05), catalase (P less than 0.01) and GSH-Px (P less than 0.001) activities. 6. The activities of lactose dehydrogenase (EC 1.1.1.27, LDH) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49, G6PDH) were found to be significantly (P less than 0.05 and P less than 0.01 respectively) increased in Cu-deficient animals and G6PDH activity was significantly (P less than 0.01) decreased as a result of lactose consumption. 7. The observed changes in antioxidant enzyme activities associated with both Cu deficieny and lactose consumption may have important implications for the development of free radical mediated cell damage. However, no significant differences in either hepatic or cardiac levels of thiobarbituric acid reactive substances, a measure of lipid peroxidation, were found.
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PMID:Effects of copper deficiency on hepatic and cardiac antioxidant enzyme activities in lactose- and sucrose-fed rats. 253 51


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