Search results for "Glutathione reductase"
showing 9 items of 69 documents
Determination of Plasma Lipid Hydroperoxides by an NADPH/NADP + Coupled Enzyme Reaction System. Evaluation of a Method
1998
Summary: Several techniques based on different principles have been proposed to measure lipid hydroperoxides. Enzymatic methods are sensitive and can be quite specific but they are subject to interference by inhibitors and not all are stoichiometric. The present work proposes some modifications of the Heath & Tappel (Anal Biochem 1976; 7:184—91) enzymatic method of determination of lipid hydroperoxides in order to standardize and automate it and to meet the analytical criteria required for a biological assay. The proposed new protocol and the automated assay give acceptable within-run and between-run precisions, with coefficients of variation of 3.34% and 5.80%, respectively, at the usual p…
Early reductive stress followed by a late onset oxidative stress in acute myocardial infarction
2018
Introduction The idea that the cells might suffer from reductive rather than oxidative stress and that such stress may be relevant in pathophysiology has gained momentum. Aim We aimed at studying markers of oxidative stress and damage as well as the expression of antioxidant enzymes in a swine model of acute myocardial infarction (AMI) followed by reperfusion. Results and Discussion We found an increase in the GSH to GSSG ratio, a decrease in protein glutathionylation and a decrease in p38 MAPK phosphorylation after 90 minutes of ischaemia in heart samples. It was accompanied by an increase in the expression of Thioredoxin (TrX) and Peroxiredoxin (PrX) and a decrease in the expression of Gl…
[23] Ratio of reduced to oxidized glutathione as indicator of oxidative stress status and DNA damage
1999
Publisher Summary This chapter discusses the ratio of reduced to oxidized glutathione (GSH) as an indicator of oxidative stress status and DNA damage. Several methods have been proposed for the determination of GSH status in biological samples. Accurate determination of this status is largely dependent on the prevention of GSH autoxidation during sample processing. As the disulfide form (GSSG) is present only in minimal amounts with respect to the reduced form, a small GSH autoxidation during sample processing can give erroneously high GSSG level. The chapter describes high-performance liquid chromatography (HPLC) method for determining GSSG. It also presents a method for glutathione determ…
[21] Assay of blood glutathione oxidation during physical exercise
1995
Publisher Summary This chapter describes a method to accurately measure glutathione (GSH) and glutathione disulfide (GSSG) in the blood of humans and animals that perform physical exercise. With this method, it is possible to assess the oxidative stress associated with physical exercise by measuring changes in the blood GSH/GSSG ratio. Glutathione measurement is performed by a modification of the glutathione S -transferase method of Brigelius et al. This is based on the conjugation of chlorodinitrobenzene with GSH catalyzed by glutathione S -transferase. The adduct formed, S-(2,4-dinitrophenyl)glutathione, exhibits a maximum of absorbance at 340 nm. The precipitation of proteins is carried …
Prolonging in utero-like oxygenation after birth diminishes oxidative stress in the lung and brain of mice pups☆
2013
Background Fetal-to-neonatal transition is associated with oxidative stress. In preterm infants, immaturity of the antioxidant system favours supplemental oxygen-derived morbidity and mortality. Objectives To assess if prolonging in utero-like oxygenation during the fetal-to-neonatal transition limits oxidative stress in the lung and brain, improving postnatal adaptation of mice pups. Material and methods Inspiratory oxygen fraction (FiO2) in pregnant mice was reduced from 21% (room air) to 14% (hypoxia) 8–12 h prior to delivery and reset to 21% 6–8 h after birth. The control group was kept at 21% during the procedure. Reduced (GSH) and oxidized (GSSG) glutathione and its precursors [γ-glut…
Glutathione-dependent resistance of the European eel Anguilla anguilla to the herbicide molinate
2001
Eels of species Anguilla anguilla were exposed to 5/4 LC50 (41.8 mg/l) of the herbicide molinate for 96 h in a time to death (TTD) test. Glutathione content (GSx, GSH, GSSG), glutathione reductase (GR) and gamma-glutamyl transpeptidase (gamma-GT) activities were determined in the liver and muscle tissues of dead and surviving (intoxicated) animals and compared to control values (non-exposed eels). TTD was positively correlated to hepatic GSH, GSH:GSSG ratio, hepatic and muscular GR, but negatively correlated to muscular GSH, which was severely depleted. Furthermore, glutathione and enzyme activities were intercorrelated, especially GSH and GR. These results indicate that eels which were abl…
Hyperoxemia caused by resuscitation with pure oxygen may alter intracellular redox status by increasing oxidized glutathione in asphyxiated newly bor…
2002
In a prospective, randomized, blinded trial we have studied the effects of resuscitation upon oxygenation in a group of asphyxiated newly born infants receiving room air or 100% oxygen as the gas source. During the acute phase of asphyxia and until the resuscitation procedure concluded, we determined serial blood gases as well as reduced and oxidized glutathione, enzymes involved in the glutathione redox cycle, and antioxidant enzyme activities. The use of 100% oxygen caused a remarkable increase of partial pressures of oxygen in arterial blood, with values that were frequently above physiological levels (>100 mm Hg). In addition, we have found a significant correlation between hyperoxemia …
Increased susceptibility to lipid peroxidation in skeletal muscles of dystrophic hamsters.
1989
The results showed that the total content of lipids, which could be peroxidized with Fe(2 +)/ascorbate stimulation in vitro, was 45.4% and 53.7% higher than normal in the dystrophic hamster muscle at the age of 1 and 3 months, respectively. Correspondingly, the susceptibility to lipid peroxidation (stimulated by ADP-chelated iron at 37 degrees C) was 38.6-74.3% higher in dystrophic muscles. The increases were not related to necrotic lesions and inflammation observed. The activities of glucose-6-phosphate dehydrogenase, glutathione reductase, thioredoxin reductase and catalase were increased in dystrophic muscles but those of superoxide dismutases and glutathione peroxidase were unaffected.
Aplidin® induces JNK-dependent apoptosis in human breast cancer cells via alteration of glutathione homeostasis, Rac1 GTPase activation, and MKP-1 ph…
2006
Aplidin® is an antitumor agent in phase II clinical trials that induces apoptosis through the sustained activation of Jun N-terminal kinase (JNK). We report that Aplidin® alters glutathione homeostasis increasing the ratio of oxidized to reduced forms (GSSG/GSH). Aplidin® generates reactive oxygen species and disrupts the mitochondrial membrane potential. Exogenous GSH inhibits these effects and also JNK activation and cell death. We found two mechanisms by which Aplidin® activates JNK: rapid activation of Rac1 small GTPase and downregulation of MKP-1 phosphatase. Rac1 activation was diminished by GSH and enhanced by L-buthionine (SR)-sulfoximine, which inhibits GSH synthesis. Downregulatio…