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

After demonstrating that prenatal exogenous thyroid hormone administration to pregnant rats produces decreases in fetal lung antioxidant enzyme (AOE) development despite increases in surfactant development, we examined the role of endogenous thyroid hormones on the development of these two lung systems. We administered the antithyroid drug methimazole (or diluent) to pregnant rats for the final 3 days before premature or term delivery; in a second series of experiments, propylthiouracil was administered for the 10 days before delivery. Both antithyroid drugs, known to cross the placenta, produced significantly decreased thyroid hormone levels in the pregnant dams. Fetal offspring from methimazole-, and propylthiouracil-treated dams demonstrated significant increases in pulmonary superoxide dismutase activity at 20 and 21 days of gestation and in catalase and glutathione peroxidase activities at 21 days compared with control offspring. Surfactant, measured as lung tissue disaturated phosphatidylcholine, was not different between either experimental group and controls. These results suggest that thyroid blockade increases AOE because the influence of thyroid hormone on AOE development may be one of depression. The findings confirm that certain hormonal regulators may influence different developing fetal lung systems in different ways.
 ...
PMID:Thyroid inhibition and developmental increases in fetal rat lung antioxidant enzymes. 276 20

A sex difference characterized by a female advantage in the maturation of the fetal pulmonary surfactant system is well documented. Because the surfactant system and the antioxidant enzyme system of the fetal lung have chronologically similar developmental patterns and share some of the same hormonal regulators, such as glucocorticoids, we questioned whether a sex difference would be present in antioxidant enzyme maturation as it is in surfactant system maturation. We studied fetal rabbits at days 26 and 28 of a 31-day gestational period. Fetal sex was identified histologically. Fetal lung lavage was performed and lavage fluid assayed for phosphatidylcholine, disaturated phosphatidylcholine, and sphingomyelin. Lung tissue from separate fetuses was assayed for disaturated phosphatidylcholine content and total phospholipid content and for the activities of three antioxidant enzymes--superoxide dismutase, catalase, and glutathione peroxidase. No differences were present in antioxidant enzyme maturation between male and female fetal rabbits at the gestational days studied. A female advantage was observed in the lung lavage disaturated phosphatidylcholine/sphingomyelin ratio (at 26 days: female 1.38 +/- 0.42, male 0.99 +/- 0.26; and at 28 days: female 3.29 +/- 0.53; male 2.26 +/- 0.35, p less than 0.05). A female advantage in surfactant development was not reflected in lung tissue disaturated phosphatidylcholine or total phospholipid. We conclude that, unlike the development of the surfactant system, the development of the antioxidant enzyme system in the fetal rabbit lung does not demonstrate a sex difference.
 ...
PMID:Lack of sex differences in antioxidant enzyme development in the fetal rabbit lung. 277 4

The effects of culture duration on primary cultured mouse hepatocyte antioxidant levels (superoxide dismutase, catalase, glutathione peroxidase, vitamin E, and glutathione) and susceptibility to glucose oxidase (GO)- and hydrogen peroxide (H2O2)-induced cell killing and lipid peroxidation were examined. Membrane fatty acid composition was also evaluated. Adult male B6C3F1/CrlBR mouse hepatocytes were isolated by collagenase perfusion of the liver and cultured on 60-mm plastic dishes in Leibovitz's L-15 medium supplemented with glucose (1 mg/ml), dexamethasone (1 microM), fetal bovine serum (10%, v/v), and gentamicin sulfate (50 micrograms/ml) for 0 hr (freshly isolated cells) to 96 hr. Hepatocyte toxicity (determined by lactate dehydrogenase release and lipid peroxidation) after a 2-hr exposure to GO (0.8-80 micrograms/ml) or H2O2 (1-5 mM) decreased with increased time in culture. This decreased hepatocyte sensitivity to GO and H2O2 toxicity was not related to antioxidant enzyme activity since superoxide dismutase, catalase, and glutathione peroxidase declined during the 96-hr culture period. In contrast, glutathione and vitamin E levels in the cultured hepatocytes rose to 274.9 +/- 8.3% and 220.6 +/- 18.6% of the levels in freshly isolated cells (129.6 +/- 11.5 nmol and 0.10 +/- 0.01 nmol per 10(6) hepatocytes, respectively). The percentage of polyunsaturated fatty acids in hepatocyte phospholipids and triglycerides decreased with culture duration while the percentage of oleic acid increased in esterified and free fatty acid pools after 2 hr in culture. Total fatty acids were not affected by time in culture. These results suggest that the decreased hepatocyte susceptibility to the toxic effects of hydrogen peroxide may have been due to elevations in cellular GSH and vitamin E levels and decreases in membrane polyunsaturated fatty acids. The data also indicate that hepatocytes in primary culture undergo changes in antioxidant levels and fatty acid composition that may affect free radical toxicity at different times in culture.
 ...
PMID:Effects of culture duration on hydrogen peroxide-induced hepatocyte toxicity. 278 69

Evidence has been obtained that implicates the generation of reactive oxygen species as an early and critical event in the promotion of neoplastic transformation in mouse JB6 cells. The time courses for specific inhibition by CuZn-superoxide dismutase (CuZn-SOD) of the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced promotion of neoplastic transformation in JB6 cells and for changes in antioxidant enzyme activities associated with TPA-exposure were examined. The antipromoting effect of CuZn-SOD was found to be critically dependent on the time of addition of CuZn-SOD relative to the start of a 14-day exposure of cells to TPA. Treatment of JB6 P+ Clone 22 and Clone 41 cells with CuZn-SOD for 18 h before, simultaneously with or up to 1 h after exposure to TPA, all inhibited promotion of transformation maximally. Delay of addition of CuZn-SOD by 2 h or more after the start of TPA treatment resulted in a marked decrease in the promotion inhibitory effect. CuZn-SOD added 24 or 48 h after TPA had no effect on promotion of transformation. Exposure of JB6 cells to 0.2- (superoxide anion radical) generated exogenously by the aerobic xanthine oxidase reaction resulted in promotion of neoplastic transformation that was prevented by concurrent addition of CuZn-SOD. Taken together these studies provide evidence that increased superoxide anion generation within the first 2 h following TPA exposure is an essential event in promotion of transformation in JB6 cells. Upon TPA exposure, JB6 Clone 41 cells exhibited time-specific activity changes in the cellular SOD, glutathione peroxidase (GSH-Px), and catalase. SOD and GSH-Px activities were reduced to 54% and 26% respectively of basal levels within 2 h of TPA treatment. GSH-Px activity recovered to basal levels within 4 h and CuZn-SOD within 48 h. Catalase activity was maximally reduced to 50% of basal within 1 h after TPA treatment and rebounded to greater than basal levels within 4 h. It is postulated that a c-kinase-dependent event induces rapid elevation of superoxide anion following TPA exposure and that this leads to reduced activity of antioxidant enzymes. Since antipromotion by exogenous CuZn-SOD is effective only during the first 2 h following TPA exposure, this suggests that the promotion-relevant 0.2- elevation is transient.
 ...
PMID:Early superoxide dismutase-sensitive event promotes neoplastic transformation in mouse epidermal JB6 cells. 282 3

The activities of Cu,Zn-superoxide dismutase, Mn-superoxide dismutase, catalase and glutathione peroxidase were comparatively studied in organ homogenates from two herbivorous fishes, viz., the grass carp and the silver carp. 2. The protein contents and lipid peroxidation of organ homogenates were also compared. The comparative measurements primarily provide control values for subsequent toxicological examinations. 3. The highest total superoxide dismutase activities were found in the kidney, spleen and liver in the grass carp, and in the kidney and liver in the silver carp. 4. The antioxidant enzyme activities and other parameters of the organ homogenates appear to be independent of the feeding mode, but are rather characteristic of the fish variety.
 ...
PMID:Comparative antioxidant enzyme study in freshwater fishes. I. Distribution of superoxide dismutase, peroxide-decomposing enzymes and lipid peroxidation in herbivorous fishes. 294 36

The activity of antioxidant enzymes were measured in alveolar type II cells isolated from control and 85% oxygen-exposed rats to determine if type II cells, an oxygen-resistant lung cell type had constitutively high enzyme activities and to measure the effect of hyperoxia on these antioxidant enzyme. Type II cells were isolated from lungs of control rats and rats exposed to 85% O2 for 7 days. In whole lungs of rats exposed to 85% oxygen there is an increase in activity (per lung or per mg lung DNA) in the antioxidant enzymes CuZn superoxide dismutase, Mn superoxide dismutase, catalase, glutathione peroxidase and glucose-6-phosphate dehydrogenase. Oxygen exposure significantly increased (p less than 0.05) all type II cell antioxidant enzyme activities when expressed per mg DNA. The protein content of oxygen exposed type II cells increased 25% from (63.9 +/- 4.8 micrograms/10(6) cells to 79.6 +/- 4.2 micrograms/10(6) cells, p less than 0.05). When type II cell enzyme activities were expressed in U/mg cell protein, only CuZn superoxide dismutase and Mn superoxide dismutase increased in activity following oxygen exposure (by 43% and 28% relative to air exposed lung type II cells, respectively, p less than 0.05). This suggested that most lung cell antioxidant enzymes increased in activity following oxidant stress in proportion to increased cell mass. CuZn and Mn superoxide dismutase increased activity to an extent greater than the increase in type II cell protein content after oxygen exposure. Alveolar macrophages lavaged from control and oxygen-exposed rats were also evaluated, and they had no significant change in CuZn and Mn superoxide dismutase activities. Type II cells accounted for 10% and 17% of alveolar cells in control and oxygen treated rats. By knowing the antioxidant enzyme activities in type II cells, the total enzyme activity of whole lung and the number of type II cells in control and oxygen exposed rats from morphometric data, we calculated the percent of whole lung enzyme activity accounted for by type II cells. Type II cells accounted for a high percentage of lung glucose-6-phosphate dehydrogenase (58% in control rats, 65% in oxygen exposed rats) but a low percentage of Mn superoxide dismutase (4% in control rats, 6% in oxygen exposed rats).
 ...
PMID:Antioxidant enzyme activity in alveolar type II cells after exposure of rats to hyperoxia. 300 82

The intracellular steady-state concentrations of hydrogen peroxide or superoxide anion were increased by inhibiting either catalase, glutathione peroxidase, or superoxide dismutase activities. Catalase was inhibited with aminotriazole while glutathione peroxidase activity was blocked by eliminating reduced glutathione after addition of either iodoacetamide diethylmaleate or phorone. The concentration of aminotriazole that stimulated chemiluminescence in 50% (60 mM) was very similar to the Ki for catalase activity (70 mM). Cyanide, an inhibitor of both catalase and superoxide dismutase, stimulated chemiluminescence in 50% at a concentration (0.15 mM) which is much closer from the Ki for superoxide dismutase (0.25 mM) than from the Ki for catalase (15 microM). The superoxide dismutase inhibitor diethyldithiocarbamate also increased chemiluminescence six- to ten-fold. Depletion of reduced glutathione stimulated spontaneous chemiluminescence when its concentration decreased below 4.5 mumol X g liver-1. The results shown herein suggest that the changes in the intracellular steady-state concentration occurring after inhibition of any antioxidant enzyme are responsible for the increased spontaneous chemiluminescence. Spontaneous chemiluminescence from intact cells may be used as a noninvasive method for monitoring intracellular free radical metabolism.
 ...
PMID:Increased spontaneous chemiluminescence from liver homogenates and isolated hepatocytes upon inhibition of O2- and H2O2 utilization. 302 9

Relative cell survival and activity of the free radical scavenging enzymes superoxide dismutase, catalase, and glutathione peroxidase were measured in cloned normal (MEA) and SV40-transformed (SVMEA) mouse embryo cells exposed at 44 degrees C for 0-3 h. At 37 degrees C, all three enzymes were 2-5 times higher in MEA than in SVMEA. Hyperthermia did not significantly alter enzyme levels in either cell line but selectively reduced transformed cell survival to less than 5% while relative survival of normal cells remained above 75%. The latter, however, could be reduced to 25% when normal cells were pretreated with 3 mM diethyldithiocarbamate, an inhibitor of copper- and zinc-containing superoxide dismutase. Similar treatment rendered SVMEA extremely thermosensitive. On the other hand, sublethal heat treatment (15 min at 45 degrees C) of cultured cells resulted in a relative thermal resistance upon subsequent exposure to 45 degrees C for 1-4 h. This induced thermotolerance was associated with a rise in antioxidant enzyme levels and both became significant only 4-6 h after the initial heat treatment. Induced enzyme and thermotolerance levels in transformed cells remained, nonetheless, far below those of normal cells. The data show that inherent (in MEA) as well as induced (in SVMEA) thermotolerance is associated with high antioxidant enzyme levels while the reverse is true in the case of inherent (in SVMEA) and induced (in MEA) thermosensitivity. These findings suggest that increased production of oxygen free radicals may be involved in hyperthermic cell injury, which then becomes a function of basal or inducible levels of antioxidant enzymes. Induction of the latter by hyperthermia is apparently inefficient in transformed cells making them more vulnerable. Enzyme induction seems also to require a lag period of 4-6 h suggesting the possible involvement of an intermediate inducer(s) at molecular level. The so-called heat shock proteins may be candidates for such a role.
 ...
PMID:Antioxidant enzymes and survival of normal and simian virus 40-transformed mouse embryo cells after hyperthermia. 303 17

The failure of adult rats to survive prolonged exposure to greater than 95% O2 is generally ascribed to the inability of their lungs to increase antioxidant enzyme synthesis in response to the oxidant challenge. We studied the synthesis rate of the antioxidant enzyme CuZn superoxide dismutase (CuZn SOD) in lungs of adult and neonatal rats exposed to conditions that alter the lung's oxidant-to-antioxidant balance. Lung CuZn SOD synthesis in the adult was significantly increased after 24 h of hyperoxia but fell to control levels after further exposure, whereas in neonatal lungs an increased rate of synthesis of CuZn SOD was found only after 72 h of hyperoxia. The adult lung responded to two in vitro oxidant stresses, [diethyldithiocarbamate exposure and heat (42 degrees C)] with increases in CuZn SOD synthesis twice the magnitude of those in the neonatal lung. These data indicate that the adult lung is at least as capable as the neonatal lung of increasing its synthesis of CuZn SOD in response to an oxidative stress. However, the inability of the adult lung to maintain an increased rate of CuZn SOD synthesis during in vivo hyperoxia may contribute to the poor tolerance of the adult lung to greater than 95% O2.
 ...
PMID:Differences in CuZn superoxide dismutase induction in lungs of neonatal and adult rats. 303 15

Preexposure of rats to sublethal levels of hyperoxia or ozone reduces morbidity and mortality when the animals are subsequently exposed to lethal levels of either oxidant stress. Lung homogenates and isolated type II pneumocytes from rats exposed to these oxidant stresses demonstrate enhanced antioxidant enzyme activities. Antioxidant enzymes, superoxide dismutase, catalase, and glutathione peroxidase are responsible for the detoxification of partially reduced oxygen species, superoxide and hydrogen peroxide, to less reactive states. Potential pulmonary cellular loci of partially reduced oxygen include mitochondrial NADH dehydrogenase, endoplasmic reticulum-derived NADPH cytochrome c reductase, and cytosolic xanthine oxido reductase. Thus partially reduced oxygen species are hypothesized to mediate hyperoxia and ozone-induced pulmonary damage. This damage may be attenuated by enhanced intracellular antioxidant enzyme activities. Pharmacologic augmentation of pulmonary antioxidant enzymes may be accomplished via intratracheal or intravascular delivery of liposomes containing antioxidant enzymes. Rats pretreated with liposomes containing both superoxide dismutase and catalase, when subsequently exposed to lethal levels of hyperoxia, demonstrate enhanced survival compared with control animals or with animals treated with control liposomes or native antioxidant enzymes. Finally, knowledge obtained from in vitro investigations optimizing liposomal delivery to specific pulmonary cell types may further aid in reducing in vivo pulmonary damage to hyperoxia and ozone.
 ...
PMID:Pulmonary metabolism of reactive oxygen species. 306 93


<< Previous 1 2 3 4 5 6 7 8 9 10