Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P30044 (antioxidant enzyme)
 8,037 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The defense system of aortic endothelial cells against oxidative stress was studied in alloxan-induced diabetic rabbits, and the effect of insulin on the antioxidant activities was estimated. Endothelial cells were prepared from 10 diabetic rabbits, 18 diabetic rabbits treated with insulin, and 10 age-matched controls after 17 days of diabetes. These cells were used for the estimation of glutathione (GSH) levels and its related enzyme activities. The antioxidant activities in these endothelial cells from diabetic rabbits were compared with those from control subjects. The concentration of GSH decreased in diabetic rabbits (1.6 +/- 0.2 nmol/mg protein [mean +/- SD] v 3.7 +/- 0.6 nmol/mg protein). Decreases in the activities of Cu, Zn-superoxide dismutase (Cu,Zn-SOD) (62.7 +/- 11.0 U/mg protein v 172.9 +/- 20.2 U/mg protein), catalase (7.6 +/- 2.1 U/mg protein v 12.3 +/- 3.2 U/mg protein), and GSH peroxidase (134.0 +/- 27.0 mU/mg protein v 179.1 +/- 26.2 mU/mg protein) were observed. The activities of other GSH-related enzymes such as GSH S-transferase or GSH reductase did not change in endothelial cells from diabetic rabbits. Most of these antioxidant activities were prevented when diabetic rabbits were treated with insulin (1 to 2 U/kg/d). These antioxidant activities were also determined in the diabetic liver and kidney. Similar decreases in the cellular defense activities and prevention of the decrease in activities by insulin were observed in the diabetic liver, while these antioxidant enzyme activities in the kidney were resistant to diabetic conditions.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of insulin on impaired antioxidant activities in aortic endothelial cells from diabetic rabbits. 140 92

A concentration-response and C x T study were undertaken to determine the effect of phosgene (COCl2) inhalation on pulmonary antioxidant processes as determined by changes in endogenous glutathione (GSH) and antioxidant-associated enzymes (GSH peroxidase, GSH reductase, glucose-6-phosphate dehydrogenase, and superoxide dismutase). Rats were exposed to 0.0, 0.1, 0.25, 0.5, and 1.0 ppm phosgene for 4 hr and 0.25 ppm phosgene for 8 hr. The endpoints were assayed at 0, 1, 2, 3 and 7 days after exposure cessation. The lowest effective concentration was 0.1 ppm phosgene (increases in measured variables from 8 to 35% above control values). At all concentrations, major effects were observed 1 to 2 days after exposure (12 to 159% above control), peaking at 2 to 3 days postexposure (11 to 253% above control), and in some cases were still evident 7 days (10 to 65% above control) after exposure. The C x T study using the same dose (120 ppm-min), but different times and concentration (0.25 ppm for 8 hr and 0.5 ppm for 4 hr), showed a concentration dependence. The peak antioxidant enzyme changes observed for the higher concentration (0.5 ppm) were at least double those observed for the lower concentration (0.25 ppm). These enzyme changes were similar to those reported for the oxidants O3 and NO2. Although the suspected mechanism of initial damage between phosgene and these oxidants is different (acylation vs oxidation) the biological result is similar (i.e., damage, repair, and influx of cells), thus eliciting similar biochemical changes in response to pulmonary injury.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of inhaled phosgene on rat lung antioxidant systems. 177 56

The resistance of human pulmonary fibroblasts (WI-38) and human umbilical vein endothelial cells to oxygen toxicity (1 atm O2) was compared. Endothelial cells were more sensitive than fibroblasts. They contained also less antioxidant enzymes except for SOD: respectively 132%, 96%, 70%, 59%, and 21% of the SOD, GSH peroxidase, GSH reductase, catalase, and G6PD content of fibroblasts. However, they contained 1.81-fold more GSH than fibroblasts. Their lower content of antioxidant enzymes can explain their higher sensitivity to oxygen. The efficiency of natural antioxidant molecules and enzymes in the protection of cells incubated 3 days under 1 atm O2 was studied. alpha-tocopherol added in the culture medium led to a significant protection, contrary to the result for ascorbic acid. Microinjection of catalase, SOD, and GSH peroxidase directly into the cells was also tested: the protection was concentration dependent for both types of cells but SOD did not protect the endothelial cells. Lower activities of the other enzymes were needed to achieve protection of the endothelial cells, compared to fibroblasts. Since endothelial cells were also shown to display lower antioxidant enzyme activities, it can be hypothesized that their content is optimized for survival in physiological conditions.
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PMID:Comparative study of oxygen toxicity in human fibroblasts and endothelial cells. 238 Feb 55

The dose and duration limiting toxic effects of cisplatin are ototoxicity and nephrotoxicity. While several studies have attempted to shed some light on the causes of nephrotoxicity, the reasons for ototoxicity induced by cisplatin are poorly understood. Therefore, this investigation was undertaken to delineate the potential mechanisms underlying cisplatin ototoxicity. The role of glutathione (GSH), oxidized glutathione (GSSG) and malondialdehyde levels, and antioxidant enzyme activities [superoxide dismutase, catalase, GSH peroxidase, and GSH reductase] were examined in cochlear toxicity following an acute dose of cisplatin. Male Wistar rats were treated with various doses of cisplatin. Pretreatment auditory brain stem evoked responses (ABR) were performed and then post-treatment ABRs and endocochlear potentials were also performed after three days. Acute cochlear toxicity (ototoxicity) was evidenced as elevated hearing thresholds and prolonged wave I latencies in response to various stimuli (clicks and tone bursts at 2, 8, 16 and 32 kHz) on ABRs. The endocochlear potentials were reduced (50% control) in cisplatin-treated rats as compared to control animals. The rats were sacrificed and cochleae isolated. The GSH, GSSG and malondialdehyde levels, and antioxidant enzyme activities were determined. Cisplatin ototoxicity correlated with a decrease in cochlear GSH [0.45 +/- 0.012 nmol/mg] after cisplatin administration compared to 0.95-012 nmol/mg in control cochleae (P < 0.05). Superoxide dismutase, catalase activities and malondialdehyde levels were significantly increased in the cochleae of cisplatin injected rats. Cochlear GSH-peroxidase and GSH reductase activity significantly decreased after cisplatin administration.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Mechanism of cisplatin ototoxicity: antioxidant system. 747 81

In this study, we examined the effects of oxidative stress adaptation on myocardial ischemic reperfusion injury. Oxidative stress was induced by injecting endotoxin (0.5 mg/kg) into the rat. After 24 h, rats were killed, hearts were isolated, and the effects of ischemia-reperfusion were studied using an isolated working heart preparation. The development of oxidative stress was examined by assessing malonaldehyde production in the heart. The antioxidant defense system was studied by estimating antioxidant enzyme activities and ascorbate- as well as thiol-dependent antioxidant reserve. The results of our study indicated that endotoxin induced oxidative stress within 1 h of treatment; the stress was reduced progressively and steadily up to 24 h. The antioxidant enzymes superoxide dismutase, catalase, glutathione (GSH) peroxidase, and GSH reductase were lowered up to 2 h and then increased. Both thiol- and ascorbate-dependent antioxidant reserve were enhanced, but the enhancement of the former was only transitory. After 24 h, endotoxin provided adequate protection to the heart from the ischemic-reperfusion injury, as evidenced by improved left ventricular function and aortic flow. Our results suggest that the induction of oxidative stress by endotoxin-induced adaptive modification of the antioxidant defense in the heart, thereby reducing ischemic-reperfusion injury.
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PMID:Myocardial adaptation to ischemia by oxidative stress induced by endotoxin. 748 60

Glutathione (GSH) content and antioxidant enzyme activities were investigated in skeletal muscle of young, adult, and old male Fischer 344 rats. Furthermore, the effect of 10 wk of exercise training on these antioxidant systems was evaluated at all ages. In the soleus muscle, GSH concentration increased markedly with age, with no significant change in glutathione disulfide (GSSG) content. Training caused a 30% decrease of GSH (P < 0.05) in the soleus of young rats and a reduction of the GSH-to-GSSG ratio at all ages. Activity of gamma-glutamyl transpeptidase (GGT), a key enzyme for GSH uptake by muscle, was also significantly decreased with training. GSH, GSSG, and the GSH-to-GSSG ratio were not altered with aging or training in the deep portion of vastus lateralis muscle (DVL). Activities of GSH peroxidase (GPX), GSSG reductase (GR), superoxide dismutase (SOD), catalase (CAT), and GSH sulfur-transferase were increased significantly with aging in both soleus and DVL. In DVL, training increased GPX and SOD activities in the young rats, whereas in soleus, training decreased GR and CAT activities in the adult rats and GGT and CAT activities in the old rats. Muscle lipid peroxidation was significantly increased with aging in both DVL and soleus but was not affected by training. These data indicate that aging may cause not only an overall elevation of antioxidant enzyme activities but also a fiber-specific adaptation of GSH system in skeletal muscle. Exercise training, although increasing selective antioxidant enzymes in the young rats, does not offer additional protection against oxidative stress in the senescent muscle.
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PMID:Aging and exercise training in skeletal muscle: responses of glutathione and antioxidant enzyme systems. 806 52

We compared oxidant-induced intracellular adenine nucleotide catabolism and cell membrane injury in 4 different human cell types. Responses to oxidant exposure were correlated with endogenous antioxidant enzyme activities in these cells. Blood monocytes, amniotic fibroblasts, umbilical vein endothelial cells in primary culture, and transformed bronchial epithelial cells (BEAS 2B) were exposed to 0.1-5 mM hydrogen peroxide (H2O2) for 4 h. Some experiments were conducted in cells pretreated with 3-amino 1:2,4-triazole (ATZ) to inactivate catalase or with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) to inactivate glutathione (GSH) reductase. Depletion of adenine nucleotides and accumulation of their catabolic products (hypoxanthine, xanthine and uric acid) occurred to varying extent, monocytes being the most resistant. There was a mutual relationship between catalase and GSH reductase activities and maintenance of cellular adenine nucleotide levels during H2O2 exposure. GSH reductase inhibition rendered BEAS 2B cells susceptible to lytic injury by H2O2, assessed by release of lactate dehydrogenase and intact nucleotides into the medium, there was no correlation between these markers of such injury and endogenous antioxidant enzymes. We conclude that adenine nucleotide depletion and nucleotide catabolite accumulation relate closely with the antioxidant enzyme activities, whereas the lack of a similar correlation between the enzyme levels and markers of lytic cell injury suggest that intracellular antioxidant enzymes do not protect cells from membrane damage due to extracellular oxidants.
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PMID:Intracellular high energy metabolite depletion and cell membrane injury with antioxidant enzymes during oxidant exposure in vitro. 865 Jun 98

Liver antioxidant enzyme activities, mRNA abundance, and glutathione (GSH) status were investigated in male Sprague-Dawley rats placed in an enclosure module aboard Space Shuttle STS-63 for 8 d (F, n = 6). F animals were compared to rats housed in an enclosure module on the ground (G, n = 9), which simulated the vibration and temperature conditions associated with launch and flight, and rats kept under conventional ground vivarium conditions in individual cages (V, n = 6). Spaceflight significantly decreased catalase, GSH reductase, and GSH sulfur-transferase activities in the liver (p < .05). Neither enzyme activity nor enzyme protein content of Cu-Zn and Mn superoxide dismutase (SOD) was affected by flight. The relative abundance of mRNA for Cu-Zn SOD and catalase was significantly decreased comparing F with G rats (p < .05). Spaceflight resulted in a dramatic decrease of liver GSH, glutathione disulfide, and total GSH contents (p < .01), which were accompanied by a lower gamma-glutamyl transpeptidase activity (p < .05). F rats showed a 47% (p < .05) increase in liver malondialdehyde concentration compared to G and V rats. Liver protein content was not affected by flight. These results indicate that spaceflight can downregulate antioxidant defense capacity and elicit an oxidative stress in the liver.
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PMID:Spaceflight downregulates antioxidant defense systems in rat liver. 943 15

Oxidative stress is implicated in several pathologies such as AIDS, Alzheimer's disease, and Parkinson's disease, as well as in normal aging. As a model system to study the response of cells to oxidative insults, glutamate toxicity on a mouse nerve cell line, HT-22, was examined. Glutamate exposure kills HT-22 via a nonreceptor-mediated oxidative pathway by blocking cystine uptake and causing depletion of intracellular glutathione (GSH), leading to the accumulation of reactive oxygen species and, ultimately, apoptotic cell death. Several HT-22 subclones that are 10-fold resistant to exogenous glutamate were isolated and the mechanisms involved in resistance characterized. The expression levels of neither heat shock proteins nor apoptosis-related proteins are changed in the resistant cells. In contrast, the antioxidant enzyme catalase, but not glutathione peroxidase nor superoxide dismutase, is more highly expressed in the resistant than in the parental cells. In addition, the resistant cells have enhanced rates of GSH regeneration due to higher activities of the GSH metabolic enzymes gamma-glutamylcysteine synthetase and GSH reductase, and GSH S-transferases activities are also elevated. As a consequence of these alterations, the glutamate resistant cells are also more resistant to organic hydroperoxides and anticancer drugs that affect these GSH enzymes. These results indicate that resistance to apoptotic oxidative stress may be acquired by coordinated changes in multiple antioxidant pathways.
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PMID:Cellular mechanisms of resistance to chronic oxidative stress. 964 Dec 55

Quinalphos (QP), an organophosphate pesticide, is used in controlling the pests of a variety of crops. To understand the mechanism of the metabolic basis of the toxicity of QP it was thought pertinent to study the role of cytochrome P-450 (P450) and antioxidant enzyme systems. Albino rats treated orally with QP (0.52 and 1.04 mg/kg body weight) for 60 days showed a significant decrease in body, brain and liver weights. Hepatic P450 content and its dependent monooxygenases, namely aryl hydrocarbon hydroxylase (AHH) and ethoxyresorufin-O-deethylase (ERD), were induced to 1.8-2.5-fold, while neuronal AHH was induced to 1.8-fold following QP treatment (1.04 mg/kg) to animals. The hepatic antioxidant defence system, comprising catalase, glutathione (GSH) reductase, superoxide dismutase (SOD) and GSH peroxidase, was also significantly increased in QP-treated animals, while in the brain only catalase was increased and GSH reductase decreased. There was no significant change in hepatic GSH content and lipid peroxide levels in QP treated animals at any dose group in comparison with the control group. Pretreatment of rats with phenobarbitone (PB) or 3-methylcholanthrene (MC) (P450 inducers) prevented mortality caused by the LD50 dose of QP, whereas pretreatment with cobalt chloride (a P450 inhibitor) enhanced the mortality rate to 100% within 3 days. From the above study it can be inferred that the toxicity of QP may be due to the parent compound or its metabolite(s) produced prior to P450 oxidation and that the induction of P450 system by QP may be a defence mechanism.
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PMID:Role of cytochrome P-450 in quinalphos toxicity: effect on hepatic and brain antioxidant enzymes in rats. 966 19


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