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)

Whereas glucocorticoid administration to pregnant rats produces parallel acceleration of lung surfactant and antioxidant enzyme system maturation in late gestation, prenatal thyroid hormone treatment results in acceleration of surfactant maturation, with a paradoxical decrease in antioxidant enzyme (AOE) development. In these studies, we tested whether prenatal thyroid releasing hormone (TRH) treatment would act like prenatal thyroid hormone on pulmonary surfactant and AOE system maturation and whether combined prenatal treatment with TRH plus dexamethasone (DEX) would alter these effects. Secondly, we tested whether prenatal TRH and prenatal TRH plus DEX would inhibit the ability of newborn rats to respond to hyperoxia with protective increases in AOE activities. Results of the developmental studies revealed significantly increased fetal lung disaturated phosphatidylcholine content with significantly decreased pulmonary AOE activities as a result of prenatal TRH treatment that was not reversed with the addition of DEX. Combined TRH plus DEX treatment resulted in statistically significant decreases in body weight, lung weight, and lung weight to body weight ratios at both 21 and 22 d of gestation; growth effects were not seen with TRH alone. In terms of hyperoxic AOE response, despite being born with lower baseline AOE levels, the newborn animals prenatally treated with TRH or TRH plus DEX were able to induce a normal pulmonary AOE response to high O2 exposure. Although requiring further investigation, this reassuring finding suggests that clinical prenatal therapy with TRH or the combination of TRH plus DEX is not contraindicated for those infants delivered prematurely who go on to require intensive hyperoxic therapy.
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PMID:Prenatal hormone treatment with thyrotropin releasing hormone and with thyrotropin releasing hormone plus dexamethasone delays antioxidant enzyme maturation but does not inhibit a protective antioxidant enzyme response to hyperoxia in newborn rat lung. 180 47

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.
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PMID:Thyroid inhibition and developmental increases in fetal rat lung antioxidant enzymes. 276 20

The surfactant system and antioxidant enzyme system of the lung have chronologically similar developmental patterns, and the maturation of both systems is accelerated by glucocorticoid hormones. To investigate whether thyroid hormone might also stimulate the development of the antioxidant enzyme system as well as the surfactant system, we injected pregnant rats with triiodothyronine (T3) or diluent. Fetal T3 offspring demonstrated significantly elevated T3 levels, had significantly increased lung tissue disaturated phosphatidylcholine (DSPC) and total phospholipid content, yet had significantly decreased activities of three lung antioxidant enzymes (AOE) (superoxide dismutase, catalase, and glutathione peroxidase). When dexamethasone was administered in combination with T3, fetuses demonstrated increases in lung DSPC content but decreases in AOE of magnitude equivalent to or greater than that seen with T3 alone. These findings indicate that thyroid hormone affects surfactant and AOE development in opposite ways and may have potentially harmful as well as beneficial effects on different aspects of lung development.
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PMID:Thyroid hormone depresses antioxidant enzyme maturation in fetal rat lung. 366 54

In newborn rats, antenatal thyroid stimulation with thyroid-releasing hormone is associated with developmental decreases in pulmonary antioxidant enzyme activities and decreased survival rates during prolonged hyperoxic exposure, with pathologic evidence of increased O2-induced lung damage. Propylthiouracil (PTU), in addition to its antithyroid effects, reportedly has antioxidant properties. To explore possible pulmonary protective effects from both the antithyroid and antioxidant properties of PTU, we administered PTU (0.015%) in drinking water to timed-pregnant rats for the final 10 d of gestation and during lactation; control rats received untreated water. The survival rate of the PTU-treated pups when placed in more than 95% O2 at birth was consistently higher at all time periods in hyperoxia from 6 d [PTU, 81 of 81 (100%); control pups, 70 of 84 (83%); p < 0.01] to 14 d [PTU, 41 of 53 (77%); control pups = 14 of 56 (25%); p < 0.01]. Further evidence of increased tolerance to more than 95% O2 in PTU pups included a significant decrease in the incidence of microscopic intraalveolar edema, decreased lipid peroxidation (malondialdehyde), and a significant increase in lung tissue surfactant-related phospholipids compared with O2-exposed control pups. No differences were present in lung structural maturation, antioxidant enzyme activity response to hyperoxia, or lung tissue O2 radical formation in more than 95% O2. We conclude that PTU treatment has important postnatal effects that protect newborn rats against oxidant-induced lung injury and lethality during hyperoxia, which may be related to PTU inhibition of thyroid hormone production, effect on O2 metabolism, or its direct antioxidant properties.
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PMID:Propylthiouracil treatment decreases the susceptibility to oxygen radical-induced lung damage in newborn rats exposed to prolonged hyperoxia. 806 33

This study shows that superoxide dismutase is present in the thyroid gland of pigeons as a constitutive enzyme serving as an antioxidant against oxygen toxicity. Exogenous administration of thyrotropin induced thyroidal superoxide dismutase with a simultaneous burst in superoxide anion radical levels during the initial phase of hormone treatment. The superoxide radical generated was completely scavenged by SOD during the late phase of TSH-treatment, presumably as an adaptive measure to check the oxygen burst. TSH failed to augment serum T3 levels, although the thyroxine level in the serum was elevated. The peak level of SOD activity profile in the thyroid gland correlated very well with the peak level of thyroxine concentrations in the serum of pigeon. It is reasonable to postulate that the thyroidal SOD in homeotherms serves a dual role, firstly as a strategic antioxidant enzyme to protect the thyroid gland against the degenerative influence of toxic oxyradicals and secondly to provide H2O2 for thyroid hormone biosynthesis. Our results confirm the previous observations that TSH is mainly thyrotropic in birds and that it has no influence on the peripheral activation of thyroxine to triiodothyronine by stimulating the extra thyroidal 5'-deiodinase activity.
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PMID:Regulation of superoxide anion radical-superoxide dismutase system in the avian thyroid by TSH with reference to thyroid hormonogenesis. 934 97

Selenium functions within mammalian systems primarily in the form of selenoproteins. Selenoproteins contain selenium as selenocysteine and perform a variety of physiological roles. Eleven selenoproteins have been identified: cellular or classical glutathione peroxidase; plasma (or extracellular) glutathione peroxidase; phospholipid hydroperoxide glutathione peroxidase; gastrointestinal glutathione peroxidase; selenoprotein P; types 1, 2, and 3 iodothyronine deiodinase; selenoprotein W; thioredoxin reductase; and selenophosphate synthetase. Of these, cellular and plasma glutathione peroxidase are the functional parameters used for the assessment of selenium status. Glutathione peroxidases catalyze the reduction of peroxides that can cause cellular damage. Thioredoxin reductase provides reducing power for several biochemical processes and defends against oxidative stress. Selenoprotein P appears to play a role in oxidant defense. Selenoprotein W may play a role in oxidant defense and be involved with muscle metabolism. Thyroid deiodinases function in the formation and regulation of active thyroid hormone. Selenophosphate synthetase is an enzyme required for the incorporation of selenocysteine into selenoproteins. In addition, a protein in the sperm mitochondrial capsule, which is vital to the integrity of sperm flagella, may be a unique selenoprotein. Recommended intakes, food sources, and status assessment of selenium, as well as selenium's role in health and disease processes, are reviewed.
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PMID:The diverse role of selenium within selenoproteins: a review. 1076 94

Peripheral metabolism of thyroid hormones is a critical component of the impact these hormones have on intracellular function. Thyroid hormones can be metabolized in peripheral tissue by deiodination, conjugation, deamination, and decarboxylation enzyme reactions. Therefore, alterations in these metabolic pathways might significantly impact the quantity of specific thyroid hormone metabolites influencing function at the cellular level. Available evidence also suggests that, under some circumstances, the activity of hepatic antioxidant enzyme systems and lipid peroxidation might influence the peripheral metabolism of thyroid hormones. Several syndromes, such as "euthyroid sick syndrome" and "low T3 syndrome," have been classified within the medical literature. The common feature of these disorders is a low level of circulating T3, with generally normal to slightly elevated blood T4 levels and either normal or slightly suppressed TSH levels. This pattern of altered thyroid hormone levels is generally agreed to be a result of impairment in extra-thyroidal peripheral metabolism. Hepatic and renal pathology, as well as catabolic states such as those induced subsequent to severe injury, illness, or trauma result in consistent shifts in the thyroid hormone profile, secondary to their impact on peripheral enzyme pathways. Lifestyle factors, such as stress, caloric restriction, and exercise, influence peripheral metabolism of thyroid hormones. Exposure to toxic metals, chemical poisons, and several drugs can also influence the peripheral fate of thyroid hormones. While the role of vitamins, minerals, and botanical extracts in thyroid hormone metabolism requires further elucidation, current evidence supports a role for selenium in the hepatic 5'-deiodination enzyme.
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PMID:Peripheral metabolism of thyroid hormones: a review. 1095 78

Selenium is of fundamental importance to human health. It is an essential component of several major metabolic pathways, including thyroid hormone metabolism, antioxidant defence systems, and immune function. The decline in blood selenium concentration in the UK and other European Union countries has therefore several potential public health implications, particularly in relation to the chronic disease prevalence of the Western world such as cancer and cardiovascular disease. Ten years have elapsed since recommended dietary intakes of selenium were introduced on the basis of blood glutathione peroxidase activity. Since then 30 new selenoproteins have been identified, of which 15 have been purified to allow characterisation of their biological function. The long term health implications in relation to declining selenium intakes have not yet been thoroughly examined, yet the implicit importance of selenium to human health is recognised universally. Selenium is incorporated as selenocysteine at the active site of a wide range of selenoproteins. The four glutathione peroxidase enzymes (classical GPx1, gastrointestinal GPx2, plasma GPx3, phospholipid hydroperoxide GPx4)) which represent a major class of functionally important selenoproteins, were the first to be characterised. Thioredoxin reductase (TR) is a recently identified seleno-cysteine containing enzyme which catalyzes the NADPH dependent reduction of thioredoxin and therefore plays a regulatory role in its metabolic activity. Approximately 60% of Se in plasma is incorporated in selenoprotein P which contains 10 Se atoms per molecule as selenocysteine, and may serve as a transport protein for Se. However, selenoprotein-P is also expressed in many tissues which suggests that although it may facilitate whole body Se distribution, this may not be its sole function. A second major class of selenoproteins are the iodothyronine deiodinase enzymes which catalyse the 5'5-mono-deiodination of the prohormone thyroxine (T4) to the active thyroid hormone 3,3'5-triiodothyronine (T3). Sperm capsule selenoprotein is localised in the mid-peice portion of spermatozoa where it stabilises the integrity of the sperm flagella. Se intake effects tissue concentrations of selenoprotein W which is reported to be necessary for muscle metabolism. It is of great concern that the health implications of the decline in Se status in the UK over the past two decades have not been systematically investigated. It is well recognised that dietary selenium is important for a healthy immune response. There is also evidence that Se has a protective effect against some forms of cancer; that it may enhance male fertility; decrease cardiovascular disease mortality, and regulate the inflammatory mediators in asthma. The potential influence of Se on these chronic diseases within the European population are important considerations when assessing Se requirement.
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PMID:Selenium, selenoproteins and human health: a review. 1168 52

The short-term action of thyroid hormone tri-iodothyronine (T3) was studied in vivo and in vitro on antioxidant enzyme activities in a teleost Anabas testudineus (Bloch). T3 injection in vivo (200 ng) in normal fish decreased the lipid peroxidation products and increased superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) activities after 30 min. T3 in vitro (10(-6) M) increased the antioxidant activities of catalase, glutathione reductase (GR), GPx and glutathione level after 15/30 min, except SOD, substantiating in vivo effects in normal fish. The results suggest a rapid regulatory effect of thyroid hormone in vivo and in vitro, in the removal of reactive oxygen species in A testudineus.
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PMID:Rapid regulatory effect of tri-iodothyronine (T3) on antioxidant enzyme activities in a fish Anabas testudineus (Bloch): short-term in vivo and in vitro study. 1695 60

Manganese (Mn) is an essential trace nutrient that is potentially toxic at high levels of exposure. As a constituent of numerous enzymes and a cofactor, manganese plays an important role in a number of physiologic processes in mammals. The manganese-containing enzyme, manganese superoxide dismutase (Mn-SOD), is the principal antioxidant enzyme which neutralizes the toxic effects of reactive oxygen species. Other manganese-containing enzymes include oxidoreductases, transferases, hydrolases, lyases, isomerases, ligases and glutamine synthetase. Environmental or occupational exposure to high levels of manganese can cause a neuropathy resembling idiopathic Parkinson's disease, commonly referred to as manganism. Manganism and Parkinson's disease are both characterized by motor deficits and damage to nuclei of the basal ganglia, particularly the substantia nigra, with altered dopamine (and its metabolites) contributing to these disorders. Dopamine, a major neurotransmitter plays a crucial role in the modulation of the cognitive function, working memory and/or attention of the prefrontal cortex and the hippocampus. Dopamine is also a known inhibitory modulator of thyroid stimulating hormone (TSH) secretion. The involvement of dopamine and dopaminergic receptors in neurodevelopment, as well as TSH modulation, led us to hypothesize that excessive manganese exposure may lead to adverse neurodevelopmental outcomes due to the disruption of thyroid homeostasis via the loss of dopaminergic control of TSH regulation of thyroid hormones. This disruption may alter thyroid hormone levels, resulting in some of the deficits associated with gestational exposure to manganese. While the effects of manganese in adult populations are relatively well documented, comprehensive data on its neurodevelopmental effects are sparse. Given the importance of this topic, we review the potential participation of thyroid hormone dyshomeostasis in the neurodevelopmental effects of manganese positing the hypotheses that manganese may directly or indirectly affect thyroid function by injuring the thyroid gland or dysregulating dopaminergic modulation of thyroid hormone synthesis.
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PMID:Effects of manganese on thyroid hormone homeostasis: potential links. 1757 15


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