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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study is undertaken to identify the regulatory switch for the activation of superoxide radical generation pathway and repression of superoxide dismutase (SOD) at the time of implantation using estrogen as a control factor and delayed implantation as a model system. The results revealed high SOD activity and negligible oxyradical generation in progesterone-treated animals on day-5 and day-8 (delayed implantation) while an enormous rise in oxyradical generation and an abrupt fall in SOD in animals which received both estrogen and progesterone injections were observed on days 5 and 8 of pregnancy. These results strongly suggest that estrogen regulates superoxide anion radical generation by lowering the SOD activity.
Biochem Mol Biol Int 1996 Aug
PMID:Estrogen surge: a regulatory switch for superoxide radical generation at implantation. 886 10

Salivary gland homogenates of the adult female mosquito Anopheles albimanus, but not those of Aedes aegypti, induced light production in the presence of NADPH and luminol, indicating a NADPH oxidase activity producing reactive oxygen species (superoxide anion) by the anopheline salivary homogenate. Superoxide production by the anopheline salivary homogenate was also confirmed by the NADPH-dependent, superoxide dismutase inhibitable, reduction of cytochrome c. The NADPH oxidase reaction measured by light production in the presence of luminol was inhibited by superoxide dismutase and catalase. Both NADH and NADPH were substrates for the production of oxygen reactive species by the salivary homogenate. Activity, as measured by luminol-dependent light emission, was enhanced one order of magnitude in the presence of 1.6 mg/ml of either phosphatidylserine or bovine serum albumin. Molecular sieving and hydroxyapatite chromatography of the salivary homogenate showed coelution of the NADPH oxidase activity with the previously reported salivary peroxidase activity. It is suggested that the salivary peroxidase of Anopheles albimanus has the ability of producing superoxide in the presence of NADPH, and this may provide the peroxidase with substrates necessary for peroxidation of vasoconstrictor amines such as serotonin, released by aggregating platelets at the site of mosquito probing and feeding.
Insect Biochem Mol Biol 1996 Jul
PMID:NAD(P)H-dependent production of oxygen reactive species by the salivary glands of the mosquito Anopheles albimanus. 899 93

A new luminescent method was used to detect the reactive oxygen species in aqueous and vitreous humors and in homogenates of the lens and retina of laboratory rats. Superoxide-like activity per microgram protein increased in all tissues with weight of the rat, a good indicator of animal age. Superoxide dismutase, centrophenoxine, soluble vitamin E (D-alpha-Locopherol (polyethlyene glycol 1000) succinate, and N'-diphenyl-p-phenylenediamine (DPPD) reduced the luminescence. Catalase had no effect. These results are consistent with the detected species being superoxide-like.
Biochem Mol Biol Int 1997 Apr
PMID:Endogenous superoxide-like species and antioxidant activity in ocular tissues detected by luminol luminescence. 911 31

In vivo administration of either 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or methamphetamine (MA) produces damage to the dopaminergic nervous system which may be due in part to the generation of reactive oxygen species (ROS). The resistance of superoxide dismutase (SOD) over-expressing transgenic mice to the effects of both MPTP and MA suggests the involvement of superoxide in the resulting neurotoxicity of both compounds. Superoxide can be converted by SOD to hydrogen peroxide, which itself can cause cellular degeneration by reacting with free iron to produce highly reactive hydroxyl radicals resulting in damage to proteins, nucleic acids and membrane phospholipids. Hydrogen peroxide has also been reported to be produced via inhibition of NADH dehydrogenase by MPP + formed during oxidation of MPTP by MAO-B and by dopamine auto-oxidation following MA-induced dopamine release from synaptic vesicles within nerve terminals. To test whether hydrogen peroxide is an important factor in the toxicity of either of these two neurotoxins, we created clonal PC12 lines expressing elevated levels of the hydrogen peroxide-reducing enzyme glutathione peroxidase (GSHPx). Elevation of GSHPx levels in PC12 was found to diminish the rise in ROS levels and lipid peroxidation resulting from MA but not MPTP treatment. Elevated levels of GSHPx also appeared to prevent decreases in transport-mediated dopamine uptake produced via MA administration as well as to attenuate toxin-induced cell loss as measured by either MTT reduction or LDH release. Our data, therefore, suggest that hydrogen peroxide production likely contributes to MA toxicity in dopaminergic neurons.
Brain Res Mol Brain Res 1997 Jun
PMID:Elevated expression of glutathione peroxidase in PC12 cells results in protection against methamphetamine but not MPTP toxicity. 919 Oct 89

Cultured human and rat endothelial cells were used to study cellular toxicity and Ca2+ signalling upon exposure to reactive oxygen species. Superoxide and hydrogen peroxide (O2.-/H2O2) were produced by the hypoxanthine/xanthine oxidase system (HX/XO) and caused intracellular Ca2+ concentration ([Ca2+]i) to rise steadily when activities above 2 mU/ml were used. These Ca2+ increases were also measured when the glucose/glucose oxidase (G/GO) system above 5 mU/ml was used to produce hydrogen peroxide (H2O2). Gross morphological changes appeared to parallel elevated [Ca2+]i levels preceding cell death. However, when HX/XO or G/GO were used at non toxic doses rapid and transient changes in [Ca2+]i were measured. These treatments did not alter subsequent receptor mediated Ca2+ signalling induced by ATP (10 microM) or histamine (100 microM). Superoxide dismutase (50 U/ml), which dismutates O2.- into H2O2 also had no influence, whereas catalase (50 U/ml), which removes H2O2, completely diminished transient [Ca2+]i responses. H2O2 added directly was able to induce similar Ca2+ transients when concentrations of at least 500 microM were used. Buffering trace amounts of iron (o-phenanthroline; 200 microM) in order to inhibit .OH radical formation was not effective to alter Ca2+ changes. Experiments performed in Ca(2+)-free buffer showed a similar rise in [Ca2+]i and readdition of Ca2+ to the extracellular medium indicated the activation of store operated Ca2+ entry. Blocking Ca(2+)-ATPases of the endoplasmatic reticulum with thapsigargin (1 microM) inhibited ROS induced transient increases and cells preincubated with pertussis toxin (200 nM) showed unchanged Ca2+ transients after exposure to both enzyme systems. Phospholipase C inhibitor U73122 (2 microM) effectively reduced hydrogen peroxide induced emptying of intracellular stores. Taken together, we demonstrate that enzymatically produced non-toxic H2O2 rather than O2.- or .OH causes calcium signalling from thapsigargin sensitive stores, and activates store operated Ca2+ entry at least partially by activating phospholipase C. These changes clearly differ from pathological 'oxidative stress' associated with a progressive increase in [Ca2+]i.
Mol Cell Biochem 1997 Jun
PMID:Transient Ca2+ changes in endothelial cells induced by low doses of reactive oxygen species: role of hydrogen peroxide. 920 90

The role of reactive oxygen species in diabetes and its complications are well known. Two therapeutic agents commonly used in the treatment of diabetes are the sulfonylureas, gliclazide and glibenclamide. These drugs effectively reduce blood sugar in non-insulin dependent diabetes millitus by augmenting insulin release. Gliclazide is known to be a general free radical scavenger as demonstrated by inhibition of o-dianisidine photo-oxidation. In this study, the effects of gliclazide and glibenclamide on free radicals were examined in vitro, using electron spin resonance (ESR) spectroscopy. Superoxide radical (O2.-) generated from hypoxanthine-xanthine oxidase system, or hydroxyl radical (.OH) generated by the Fenton reaction, were analyzed as spin adducts of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). NO was generated from 1-hydroxy-2-oxo-3-(N-3-methyl-3-aminopropyl)-3-methyl-1-triazene (NOC-7), and analyzed by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl (carboxy-PTI) produced from the reaction between 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO) and NO. Gliclazide scavenged O2.-, .OH and NO in a dose-dependent manner whereas glibenclamide was without effect. These findings suggest that gliclazide is not only effective in reducing blood sugar but also may be beneficial by inhibition of lipid and protein denaturation, which leads to the development of diabetic complications.
Res Commun Mol Pathol Pharmacol 1997 May
PMID:Gliclazide scavenges hydroxyl, superoxide and nitric oxide radicals: an ESR study. 922 46

Alacepril is an inhibitor of the angiotensin converting enzyme (ACE), and is commonly used as an antihypertensive. In this study, the effects of alacepril, its metabolites, desacetylalacepril and captopril, and also lisinopril, which has no sulfhydryl group in the structure, on free radicals were examined in vitro, using an ESR method. Superoxide and hydroxyl radical scavenging activities of alacepril metabolites, desacetylalacepril and captopril, were observed, whereas lisinopril hardly scavenged the superoxide or the hydroxyl radicals. Alacepril and its metabolites did not scavenge nitric oxide, but lisinopril showed slight scavenging activity. These findings suggest that the biological action of alacepril may be partly due to the antioxidant effect of its metabolites, having a sulfhydryl group.
Res Commun Mol Pathol Pharmacol 1997 May
PMID:Free radical scavenging properties of alacepril metabolites and lisinopril. 922 47

Placenta in mouse generate increasing quantities of superoxide dismutase from day 13 of pregnancy until parturition. This is associated with a concomitant reduction in the activity of superoxide radical. This findings points to the steroidogenic control of the later half of pregnancy by the placental axis. Parturition is associated with an abrupt spurt in superoxide radical. This is a novel finding and could be a consequence of the estrogen surge at labour. It is suggested that this abrupt increase in superoxide radical level at parturition may remould the placental membrane fluid at the point of its attachment with uterine membranes so as to facilitate the separation of placenta from uterus.
Biochem Mol Biol Int 1997 Aug
PMID:Activity profile of placental superoxide-superoxide dismutase system in pregnant mice and its possible relation with placental steroidogenesis. 928 66

The near-infrared emission spectrum of the A2A' --> X2A" transition of the hydroperoxyl radical, HO2, has been studied by Fourier transform spectrometry. The 000 --> 000 band has been recorded at high spectral resolution. DeltaKa = +/-1 subbands up to Ka' = 9 --> Ka" = 8 and Ka' = 8 --> Ka" = 9 comprising lines from rotational levels up to N' = 32 have been observed. With about a factor of 10 lower intensity, DeltaKa = 0 subbands 0-0 to 6-6 were found which are shown to be due to magnetic dipole transitions. In addition, in the 2-2 sub-band "forbidden" electric dipole lines were observed. These likely are induced by Renner-Teller interaction. Local perturbations extending over 3-10 N' values are found in the Ka' = 0-7 levels of the A2A' state. One series of perturbations is attributed to DeltaKa = 0, DeltaJ = 0 interactions with the 112 level of the X2A" ground state. Copyright 1997 Academic Press. Copyright 1997Academic Press
J Mol Spectrosc 1997 Oct
PMID:High-Resolution Study of the A2A' --> X2A" Transition of HO2: Analysis of the 000-000 Band 939 68

Manganese superoxide dismutase (MnSOD) is a mitochondrial enzyme that dismutates potentially toxic superoxide radical into hydrogen peroxide and dioxygen. This enzyme is critical for protection against cellular injury due to elevated partial pressures of oxygen. Thioredoxin (TRX) is a potent protein disulfide reductase found in most organisms that participates in many thiol-dependent cellular reductive processes and plays an important role in antioxidant defense, signal transduction, and regulation of cell growth and proliferation. Here we describe induction of manganese superoxide dismutase by thioredoxin. MnSOD mRNA and activity were increased dramatically by low concentrations of TRX (28 microM). Elevation of MnSOD mRNA by TRX was inhibited by actinomycin D, but not cycloheximide, occurring both in cell lines and primary human lung microvascular endothelial cells. mRNAs for other antioxidant enzymes including copper-zinc superoxide dismutase and catalase were not elevated, demonstrating specificity of induction of MnSOD by TRX. Thiol oxidation by diamide or alkylation by chlorodinitrobenzene inhibited MnSOD induction, further indicating a requirement for reduced TRX. Because both oxidized and reduced thioredoxin (28 microM) induced MnSOD mRNA, the intracellular redox status of externally added Escherichia coli oxidized TRX was determined. About 45% of internalized E. coli TRX was reduced, with 8% in fully reduced form and about 37% in partially reduced form. However, when TRX reductase and nicotinamide adenine dinucleotide (NADPH) were added to the extracellular medium with TRX, more than 80% of E. coli TRX was found to be in a fully reduced state in human adenocarcinoma (A549) cells. Although lower concentrations of oxidized TRX (7 microM) did not induce MnSOD mRNA, this concentration of TRX, when reduced by NADPH and TRX reductase, increased MnSOD mRNA six-fold. In additional studies, MCF-7 cells stably transfected with the human TRX gene had elevated expression of MnSOD mRNA relative to vector-transfected controls. Thus, both endogenously produced and exogenously added TRX elevate MnSOD gene expression. These findings suggest a novel mechanism involving reduced TRX in regulation of MnSOD.
Am J Respir Cell Mol Biol 1997 Dec
PMID:Elevation of manganese superoxide dismutase gene expression by thioredoxin. 940 58


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