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)

Rats weighing 45-50 g were fed 3 diets for 8 wk: a balanced control diet (CD) consisting of 4% fat (polyunsaturated/saturated fatty acids [P/S] ratio 2.9/1) and two fat-rich diets: polyunsaturated (UD)--P/S 7.6/1 and saturated (SD) P/S 0.3/1. After 8 wk feeding on the respective diets, rats were subjected to swimming for 90 min at 30 degrees C daily, 5 d/wk for 8 wk. At the end of this period, the rats were killed and the lymphoid organs (LO--thymus, spleen, and mesenteric lymph nodes) and muscles (soleus and gastrocnemius) removed for the measurement of TBARs (Thiobarbituric Acid Reactant Substances) content and of the activities of antioxidant enzymes (CuZn- and Mn-Superoxide dismutase--SOD--, catalase, and glutathione peroxidase). To evaluate the changes in the sites of generation of reducing equivalents involved in the formation of free radicals, the activities of citrate synthase and glucose-6-phosphate dehydrogenase were measured. The exercise-training clearly modified the enzyme activities and TBARs content of the lymphoid organs and skeletal muscles, but this effect was dependent upon the diet given to the rats. However, fatty acid rich diets had presented a more pronounced effect on the studied aspects than did physical activity. Although one could expect a summatory effect of polyunsaturated fatty acid-rich diet and exercise-training, swimming increased the activities of CuZn- and Mn-SOD in almost all tissues from the elevated level promoted by fat-rich diets.
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PMID:Antioxidant enzyme activities in the lymphoid organs and muscles of rats fed fatty acids-rich diets subjected to prolonged physical exercise-training. 782 70

Although endurance training enhances the antioxidant defence of different tissues, information on the effect of sprint training is scanty. We examined the effect of sprint training on rat skeletal muscle and heart antioxidant defences. Male Wistar rats, 16-17 weeks old, were sprint trained on a treadmill for 6 weeks. Total glutathione levels and activities of glutathione peroxidase, glutathione reductase, glutathione S-transferase and superoxide dismutase in heart and various skeletal muscles were compared in trained and control sedentary animals. Lactate dehydrogenase and citrate synthase enzyme activities were measured in muscle to test the effects of training on glycolytic and oxidative metabolism. Sprint training significantly increased lactate dehydrogenase activity in predominantly fast glycolytic muscles and enhanced total glutathione contents of the superficial white quadriceps femoris, mixed gastrocnemius and fast-glycolytic extensor digitorum longus muscles. Oxidative metabolic capacity increased in plantaris muscle only. Compared with the control group, glutathione peroxidase activities in gastrocnemius, extensor digitorum longus muscles and heart also increased in sprint trained rats. Glutathione reductase activities increased significantly in the extensor digitorum longus muscle and heart. Glutathione S-transferase activity was also higher in the sprint trained extensor digitorum longus muscle. Sprint training did not influence glutathione levels or glutathione-related enzymes in the soleus muscle. Superoxide dismutase activity remained unchanged in skeletal muscle and heart. Sprint training selectively enhanced tissue antioxidant defences by increasing skeletal muscle glutathione content and upregulating glutathione redox cycle enzyme activities in fast and mixed fibre leg muscles and heart.
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PMID:Skeletal muscle and heart antioxidant defences in response to sprint training. 889 59

Pre-eclampsia is a hypertensive disorder of human pregnancy that is a leading cause of premature delivery and fetal growth retardation. It is characterized by hypertension, reduced uteroplacental blood flow, proteinuria and oedema. Pre-eclampsia is associated with increased lipid peroxidation in the maternal circulation and in the placenta. Mitochondria are sources of oxygen radicals and are enriched with polyunsaturated fatty acids that are susceptible to peroxidation. Therefore, the mitochondria could be an important source of oxidative stress and lipid peroxidation. To study this, the level of lipid peroxidation in the mitochondrial fraction of placentae obtained from normally pregnant women (n=8) and women with pre-eclampsia (n=8) was examined. Placental tissues were homogenized and the mitochondrial fraction was isolated by ultracentrifugation. Mitochondrial lipid peroxides were estimated by malondialdehyde (MDA). NADPH and Fe++ were used to stimulate lipid peroxidation. Superoxide dismutase (SOD) was used to inhibit superoxide radicals and mannitol to inhibit hydroxyl radicals. The following results were found: (1) MDA levels were significantly greater in the mitochondrial fraction isolated from pre-eclamptic placentae than from normal placentae (27.4+/-3.0 versus 17.0+/-1.8 nmol/g tissue, mean+/-s.e., P<0.05); (2) the oxidative potential of the pre-eclamptic mitochondrial fraction was also higher than normal as evidenced by the significantly greater stimulation of lipid peroxidation by NADPH and Fe+ + (248+/-25 versus 164+/-35 nmol/g, P<0.05); (3) superoxide dismutase, but not mannitol, attenuated the lipid peroxidation induced by NADPH and Fe+ + demonstrating that superoxide is the radical responsible for mitochondrial lipid peroxidation in this system; and (4) the amount of mitochondrial protein was 47 per cent greater and the activity of the mitochondrial enzyme, citrate synthase, was 56 per cent greater in the pre-eclamptic placentae indicating an increase in the amount of mitochondria in the pre-eclamptic placentae. It is concluded that: (1) mitochondrial lipid peroxidation is increased in pre-eclampsia; (2) the amount of placental mitochondria is increased in pre-eclampsia; (3) placental mitochondria contribute to the abnormal increase in lipid peroxidation that occurs in pre-eclamptic placentae by both an increase in their amount and an increase in their susceptibility to oxidation; and (4) mitochondrial generation of superoxide could be an important source of oxidative stress in pre-eclampsia.
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PMID:Placental mitochondria as a source of oxidative stress in pre-eclampsia. 985 61

The antioxidant properties of North American ginseng (Panax quinquefolium) were investigated in young and old rats fed a ginseng-supplemented diet for 4 mo. Female Fischer 344 rats at 4 (Y, n = 38) or 22 (O, n = 25) mo of age were randomly divided into three groups and fed either a AIN-93G formula-based control diet (C) or a diet containing 0.5 g/kg (low dose, L) or 2.5 g/kg (high dose, H) dry ginseng power for 4 mo. Oxidant generation, measured with 2'7'-dichlorofluorescin (DCFH), was significantly lowered with ginseng feeding in the homogenates of heart, soleus, and the deep portion of vastus lateralis muscle (DVL) (P < 0.05) in both Y and O rats, and the effects were dose dependent. Superoxide dismutase activity was elevated in heart and DVL of H rats, and in soleus of L rats (P < 0.05). H rats showed higher glutathione peroxidase activity in DVL and soleus muscle (P < 0.05), and elevated citrate synthase activity in the heart of both age groups and DVL of Y rats (P < 0.05). Neither the H nor L diet affected age-dependent lipid peroxidation in the heart or muscle, but protein carbonyl content was attenuated with the H diet in the heart (P < 0.05) and with both the L and H diets in DVL (P < 0.01). We conclude that ginseng supplementation can prevent age-associated increase in oxidant production and oxidative protein damage in rats. These protective effects are explained in part by elevated antioxidant enzyme activities in the various tissues.
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PMID:Chronic ginseng consumption attenuates age-associated oxidative stress in rats. 1460 81

Superoxide dismutase (SOD)-deficient Escherichia coli was cultivated under the oxidative stress generated by photoexcited titanium dioxide. These cells showed higher growth rate and glucose consumption rate with accelerated accumulation of acetic acid in the medium, compared to the cells cultivated under the normal condition without the stress. Under the stress condition, the activity of acetate kinase and mRNA expressions of the enzymes for acetic acid production (pta and ackA) were approximately doubled, while the activity of citrate synthase and mRNA expressions of the enzymes in TCA cycle (gltA, acnA, icd, sucA, sucC, sdhA, fumA and mdh) were repressed by about half, as compared with those under the normal condition. These results suggest that the stress-suffering cells switch the metabolic pathway into a "suppressed aerobiosis", possibly for lowering the generation of reactive oxygen species.
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PMID:Metabolic alternations in SOD-deficient Escherichia coli cells when cultivated under oxidative stress from photoexcited titanium dioxide. 1833 21

Malignant astrocytoma is the most commonly occurring brain tumour in humans. Oxidative stress is implicated in the development of cancers. Superoxide dismutase 2 (SOD2) was found to exert tumour suppressive effect in basic research, but increased SOD2 protein level was associated with higher aggressiveness of human astrocytomas. However, studies reporting alterations of antioxidant enzymes in human astrocytomas often employed less accurate methods or included different types of tumours. Here we analysed the mRNA levels, activities, and protein levels of primary antioxidant enzymes in control brain tissues and various grades of astrocytomas obtained from 40 patients. SOD1 expression, SOD1 activity, and SOD1 protein level were lower in Grade IV astrocytomas. SOD2 expression was lower in low-grade (Grades I and II) and Grade III astrocytomas than in controls, but SOD2 expression and SOD2 protein level were higher in Grade IV astrocytomas than in Grade III astrocytomas. Although there was no change in SOD2 activity and a lower activity of citrate synthase (CS), the MnSOD:CS ratio increased in Grade IV astrocytomas compared with controls and low-grade astrocytomas. Furthermore, SOD1 activity, CS activity, SOD1 expression, GPX4 expression, and GPX4 protein level were inversely correlated with the malignancy, whereas catalase activity, catalase protein, SOD2 protein level, and the SOD2:CS ratio were positively correlated with the degree of malignancy. Lower SOD2:CS ratio was associated with poor outcomes for Grade IV astrocytomas. This is the first study to quantify changes of various primary antioxidant enzymes in different grades of astrocytomas at different levels concurrently in human astrocytomas.
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PMID:Alterations of the levels of primary antioxidant enzymes in different grades of human astrocytoma tissues. 2986 58