Search results for "thione"
showing 10 items of 865 documents
Role of the Well-Known Basic and Recently Discovered Acidic Glutathione S-Transferases in the Control of Genotoxic Metabolites
1991
Glutathione S-transferases (GSTs; E.C. 2. 5. 1. 18) are a family of enzymes which have increasingly attracted the interest of toxicologists, pharmacologists, biochemists and clinicians since their discovery in 1961 (1). Initially, GSTs were believed to serve as intracellular transport proteins for endogenous compounds with limited solubility in water, thus acting as an intracellular equivalent to albumin in blood plasma. In this assumed capacity of reversible binding and transport of various ligands, the corresponding protein was named ligandin (2). Following the discovery of abundant GST occurrence in most forms of aerobic life including plants, and the GST-catalysed conjugation of a wide …
Dihydrodiol Dehydrogenase: Substrate Specificity, Inducibility and Tissue Distribution
1982
The present study shows that: Dihydrodiol dehydrogenase activity is present in the 100,000 g supernatant fraction of extrahepatic tissues. Dihydrodiol dehydrogenase is able to oxidize the hydroxy group and to reduce the keto group of a number of xenobiotics including quinones derived from polycyclic aromatic hydrocarbons. Dihydrodiol dehydrogenase was not inducible by various substances including hormones, polycyclic aromatic hydrocarbons, substrates of the enzyme and potent inducers of monooxygenases, epoxide hydrolase and glutathione S-transferases. Only in the case of thyroxine was a weak induction with a high dose of the hormone observed.
Oral glutathione increases hepatic glutathione and prevents acetaminophen toxicity
1990
Administration of oral glutathione (GSH) increases hepatic GSH levels in fasted rats, in mice treated with GSH depletors such as diethylmaleate and in mice treated with high doses of paracetamol. An increase in hepatic GSH levels after administration of oral GSH does not occur in animals treated with buthionine suphoximine, an inhibitor of GSH synthesis. Administration of oral GSH leads to an increase in the concentration of L-cysteine, a precursor of GSH, in portal blood plasma. Oral administration of L-methio-nine to fasted rats produced a significant decrease of hepatic ATP, but not in fed rats. Administration of N-acetyl-cysteine or GSH did not affect the hepatic ATP levels. The results…
Age-related changes in antioxidant status and oxidative damage to lipids and dna in mitochondria of rat liver
2005
To investigate the correlation between oxidative stress and mitochondrial damage with aging, antioxidant system, levels of oxidative DNA damage and as an index of the loss of plasma membrane integrity lipid peroxidation and membrane potential were studied. Results showed that the activities of antioxidant enzymes superoxide dismutase (SOD) and catalase significantly decreased during aging, however glutathione peroxidase (GSH-PX) increased in the aged mitochondria and glutathione (GSH) did not change during aging. No statistical difference was observed in the lipid peroxidation of mitochondria between young and old animals. The level of oxidative DNA damage (measured as 8oxo-dG) tended to in…
Sex Differences in Mitochondrial Antioxidant Gene Expression
2020
Females live longer than males. This could be in part due to the higher levels of estrogens in females, which protect them against aging. Physiological concentrations of estrogens have antioxidant effects as they induce the expression of manganese superoxide dismutase and glutathione peroxidase by stimulating estrogen receptors and the mitogen-activated protein kinase and nuclear factor kappa B pathways. However, estrogens can have undesirable effects such as they are feminizing to males, so other alternatives need to be searched. Phytoestrogens are good candidates as they can also bind to estrogens receptors, and in fact, they are able to mimic the antioxidant properties of estrogens. It i…
Glutathione Peroxidase-1 and Homocysteine for Cardiovascular Risk Prediction
2005
Objectives This prospective study was designed to evaluate the effect of joint determination of two important contrary biomarkers—homocysteine and glutathione peroxidase (GPx)-1—on cardiovascular risk stratification. Background Homocysteine plasma levels have been associated with cardiovascular risk. Experimental data suggest that antioxidative GPx-1 activity modulates cardiovascular risk associated with homocysteine. Methods In 643 patients with coronary artery disease, we performed a prospective study to assess the risk of homocysteine plasma levels and GPx-1 activity on long-term cardiovascular risk with a median follow-up of 7.1 years. Results Both homocysteine and GPx-1 were among the …
Concentration-Dependent Antioxidant/Pro-Oxidant Activity of Ascorbic Acid in Chickens
2012
С vitamīns piedalās daudzos vielmaiņas procesos. Tas stiprina organisma imūnsistēmu, piedalās bioloģiskās oksidēšanās un reducēšanās procesos. Askorbīnskābe un dehidroaskorbīnskābe veido redoks sistēmu un ir saistītas ar glutationa sistēmu. Dažādu stresu ietekmē askorbīnskābes koncentrācija audos samazinās. Tādēļ barību vajag bagātināt ar šo vitamīnu. Darba mērķis bija pētīt dažādus oksidatīvā stresa biomarķierus cāļu organismā, kadmija akumulāciju orgānos, imūnsistēmas aktivitāti un nieru funkcijas izmaiņas askorbīnskābes ietekmē atkarībā no tās koncentrācijas barībā. Eksperimentos izmantojām vienu dienu vecus Lohmann Brown gailīšus, kurus sadalījām piecās analogās grupās. Cāļi saņēma komb…
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…
G6PD Overexpression Protects Mice Against Associated Oxidative Stress and Delays the Occurrence of Frailty
2016
To assess the impact of lifelong overexpression of G6PD on reactive oxygen species (ROS)-derived damage and the prevention of frailty, we measured the levels of macromolecular oxidative damage in young and old mice and the we tested the neuromuscular fitness and the grip strength in old mice. Old G6PD-Tg male and female mice showed diminished accumulation of DNA oxidation (measured as 8-hydroxyguanosine or 8-OHdG) in liver and brain. Old females also showed reduced lipid oxidation (measured as malondialdehyde or MDA) in the liver. Old G6PD-Tg males, but not females, presented a small but significant increase in brain protein carbonylation. In accordance with these findings, liver from 2-yea…
Effects of strength and endurance training on antioxidant enzyme gene expression and activity in middle-aged men
2007
This study was aimed at investigating the effects of a 21-week period of progressive strength or endurance training on peripheral blood mononuclear cells (PBMC) antioxidant enzyme gene expression and activity in healthy middle-aged untrained men. Strength (n=11) and endurance (n=12) training were performed twice a week, including resistance exercises to activate all the main muscle groups or cycle-ergometer pedaling, respectively. mRNA levels of catalase, glutathione peroxidase (GPx), mitochondrial superoxide dismutase (MnSOD) and cytosolic superoxide dismutase (CuZnSOD) were increased after 21 weeks of strength training, while endurance training induced significant changes only in MnSOD an…