Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.3.1 (citrate synthase)
 4,488 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of aging on myocardial antioxidant enzyme activity, lipid peroxidation, and other related biochemical properties were investigated in male Wistar-Furth rats at 4, 26, and 31 mo of age at rest and after an acute exercise bout. The results showed that resting heart cytosolic superoxide dismutase (CuZn SOD) activity was significantly decreased in the heart with aging (66 +/- 6.5 U/mg protein at 4 mo vs. 49 +/- 3.8 U/mg protein at 31 mo) and was elevated in all age groups after exercise. Mitochondrial Mn SOD activity was almost doubled in both 26- and 31-mo-old rats compared with that at 4 mo. Myocardial catalase and cytosolic glutathione peroxidase (GPX) activities were significantly decreased with age, whereas mitochondrial GPX was 29% higher (P less than 0.05) in 31- than 4-mo-old rats. Glutathione S-transferase activity in the heart also declined with age (P less than 0.05 at 31 mo). Malondialdehyde contents in both heart homogenate and mitochondria were significantly increased at old age. Activity of several enzymes related to myocardial energy production, e.g., citrate synthase, malate dehydrogenase, and lactate dehydrogenase, as well as myocardial protein content showed an age-related decline. These data indicate that myocardial antioxidant capacity is weakened during aging and that the compensatory increases of mitochondrial SOD and GPX may be an important mechanism in coping with free radical damage in senescent heart. Findings in the present investigation seem to support the free radical theory of aging.
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PMID:Myocardial aging: antioxidant enzyme systems and related biochemical properties. 187 97

Inhibition of metabolic enzyme activity has been associated with free radical stress in locomotor muscle with prolonged or intense exercise. However, it is not known whether such alterations with acute exercise in skeletal muscle are influenced by muscle fiber type or age. Twenty 4-mo-old and twenty 24-mo-old female Fischer-344 rats were divided at random into young exercised (YE; n = 10), old exercised (OE; n = 10), young control (YC; n = 10), and old control (OC; n = 10) groups. Animals in both YE and OE groups ran on a treadmill (10% uphill grade) for 40 min at approximately 75% of each age-group's maximal O2 consumption. Immediately after the treadmill run, white gastrocnemius (WG), red gastrocnemius (RG), and soleus (SOL) muscles were removed and quick-frozen in liquid nitrogen. Malondialdehyde was significantly increased (P < 0.05) in RG of YE vs. YC rats. Glutathione peroxidase activity was significantly elevated (P < 0.05) in the WG of YE rats. Analysis of variance revealed a significant over-all increase in superoxide dismutase activity with exercise. Activities of phosphofructokinase (PFK), citrate synthase, succinate dehydrogenase, and 3-hydroxyacyl-CoA dehydrogenase were unchanged (P > 0.05) with acute exercise in the SOL. However, PFK activity was decreased in the WG by 60% in OE but only 33% in YE, and in the RG by 41% in OE but only 21% in YE. We conclude that maximal glycolytic flux in the gastrocnemius may be adversely affected by acute exercise, and this effect was more pronounced in the 24-mo-old group.
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PMID:Acute exercise and skeletal muscle antioxidant and metabolic enzymes: effects of fiber type and age. 828 76

Emerging evidence has shown that acute heat exposure affects metabolic characteristics and causes oxidative damage to skeletal muscle in birds. Little is known, however, about such phenomena under chronic heat stress conditions. To address this, we designed the present study to determine the influence of cyclic (32 to 24 to 32 degrees C: 32 degrees C for 8 h/d, 32-24-32HS ), and constant (32 and 34 degrees C, 32HS and 34HS, respectively) heat exposure on the metabolic and peroxide status in skeletal muscle of 4-wk-old male broiler chickens. Heat stress, particularly in the 32HS and 34HS groups, depressed feed intake and growth, while cyclic high temperature gave rise to a less severe stress response in performance terms. Malondialdehyde (MDA) levels in skeletal muscle were enhanced (P<0.05) by constant heat treatment; the degree of enhancement was not as large as the changes observed in our previous 'acute' heat stress model. The 3HADH (3-hydroxyacyl CoA dehydrogenase related to fatty acid oxidation) and CS (citrate synthase) enzyme activities were lowered (P<0.05) by both the cyclic and constant 34HS treatments, and constant 34HS group, respectively. These results suggest that chronic heat exposure decreases metabolic oxidation capacity in skeletal muscle of broiler chickens. On exposure to chronic heat stress, GPx activity remained relatively constant, though a temperature-dependent elevation in Cu/Zn-SOD activity was observed, implying that anti-oxidation ability was disturbed by the chronic stress condition. From these results it can be concluded that chronic heat stress did not induce oxidative damage to a major extent. This may probably be due to a decrease in metabolic oxidation capacity or due to a self-propagating scavenging system, though the system was not fully activated.
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PMID:Metabolic characteristics and oxidative damage to skeletal muscle in broiler chickens exposed to chronic heat stress. 2003 50

The present study addresses whether exercise during pregnancy in mouse alters mitochondrial function in the brains of the resultant offspring. We divided pregnant mice into four groups: a control group and groups of mice that exercised for 20 (E20m), 30 (E30m) and 40 min/d (E40m). The pregnant mice ran on a treadmill at 12 m/min, 5 d/week for a duration of 3 weeks. The protein expression of cytochrome c oxidase subunit Va (CVa) was downregulated in the offspring of the E20m group, unlike that in the control animals, whereas CVa expression was reserved in the E40m neonates. The F1-ATPase catalytic core (Core) protein expression levels were the highest in the E40m group neonates. Complex I, IV and ATPase activities were significantly lower in the E20m group than that in the control group neonates and were reserved in the E30m and E40m group neonates. The activities of citrate synthase and pyruvate dehydrogenase were consistent with those of complex I, IV and ATPase. Peroxisome proliferator-activated receptor-gamma coactivator 1-alpha, mitochondrial transcription factor A, nuclear respiratory factor-1 and mitochondrial DNA showed high levels of expression in the E40m neonates compared with the other groups. Malondialdehyde (MDA) levels in E40m neonates were higher than that in the controls but were lower than that in the E20m neonates. Finally, 40 min/d of maternal exercise improved mitochondrial function in the resultant pups and was concomitant with brain-derived trophic factor induction in the hippocampus, thereby functionally improving short-term memory.
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PMID:Maternal exercise during pregnancy affects mitochondrial enzymatic activity and biogenesis in offspring brain. 2322 20

Many physiological adjustments occur in response to salt intake in several marine taxa, which manifest at different scales from changes in the concentration of individual molecules to physical traits of whole organisms. Little is known about the influence of salinity on the distribution, physiological performance, and ecology of passerines; specifically, the impact of drinking water salinity on the oxidative status of birds has been largely ignored. In this study, we evaluated whether experimental variations in the salt intake of a widely-distributed passerine (Zontotrichia capensis) could generate differences in basal (BMR) and maximum metabolic rates (Msum), as well as affect metabolic enzyme activity and oxidative status. We measured rates of energy expenditure of birds after 30-d acclimation to drink salt (SW) or tap (fresh) water (TW) and assessed changes in the activity of mitochondrial enzymes (cytochrome c oxidase and citrate synthase) in skeletal muscle, heart, and kidney. Finally, we evaluated the oxidative status of bird tissues by means of total antioxidant capacity (TAC) and superoxide dismutase activities and lipid oxidative damage (Malondialdehyde, MDA). The results revealed a significant increase in BMR but not Msum, which resulted in a reduction in factorial aerobic scope in SW- vs. TW-acclimated birds. These changes were paralleled with increased kidney and intestine masses and catabolic activities in tissues, especially in pectoralis muscle. We also found that TAC and MDA concentrations were ~120 and ~400% higher, respectively in the liver of animals acclimated to the SW- vs. TW-treatment. Our study is the first to document changes in the oxidative status in birds that persistently drink saltwater, and shows that they undergo several physiological adjustments that range that range in scale from biochemical capacities (e.g., TAC and MDA) to whole organism traits (e.g., metabolic rates). We propose that the physiological changes observed in Z. capensis acclimated to saltwater could be common phenomena in birds and likely explain selection of prey containing little salt and habitats associated with low salinity.
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PMID:Coping with Salt Water Habitats: Metabolic and Oxidative Responses to Salt Intake in the Rufous-Collared Sparrow. 2891 65