Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.6.1.1 (aspartate aminotransferase)
 21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of simultaneous administration of thiamine, niacin or vitamin B12 with vitamin E on plasma vitamin E levels were studied in 20 adult male volunteers belonging to the low socio-economic class. The effect of vitamin E on the nutritional status of pyridoxine, riboflavin and thiamine as judged by the erythrocyte enzymes, aspartate aminotransferase, glutathione reductase and transketolase, respectively was also studied. None of the members of the B-complex vitamins studied here had any effect on plasma vitamin E levels. This was in contrast to the observation made earlier that pyridoxine and riboflavin can reduce plasma vitamin E. There was a transient reduction in both the basal and stimulated activities of erythrocyte aspartate aminotransferase, the significance of which needs further investigation.
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PMID:Studies on interactions of vitamin E with thiamine, niacin and vitamin B12. 731 77

Serum activity of glutathione reductase (GR), glucose phosphate isomerase (GPI), aspartate aminotransferase (AST), alanine aminotransferase (ALT) phosphate alkaline (PAL), and gamma-glutamyl transferase (GGT) was studied in 142 patients, in all serum bilirubin was more than 2 mg/dl. Distribution was as follows; 68 cirrhosis of the liver; 27 acute hepatitis; 31 benign extra-hepatic biliary obstruction; and 16 neoplastic obstruction of the biliary tract without liver metastasis. Fifty-three healthy volunteer blood donors were used as the control group. Mean values for GR activity in our patients were significantly higher than those for the control group, although less so in benign obstruction (p less than 0.01) than in those with acute hepatitis (p less than 0.001), cirrhosis (p less than 0.01) and neoplasic biliary obstruction (p less than 0.001). The GPI values were higher than the control groups in patients with acute hepatitis (p less than 0.001) and obstructive neoplastic jaundice (p less than 0.02). In cases with cirrhosis, 87% presented slightly higher values of GR, while GPI was within normal levels in 93 % of all cases. In patients with acute hepatitis, 92% showed a definite increase in GPI and GR values. In 71% of those with benign biliary obstruction levels for both enzymes were normal, as they were in only 6% of those with obstructive neoplastic jaundice. These findings are statistically significant in all cases and of diagnostic value in establishing a differential enzymatic diagnosis in patients presenting with clinical and biological patterns of cholestasis.
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PMID:[Determination of serum activity of glucose phosphate isomerase and glutathione reductase in intra and extra hepatic cholestasis.(author's transl)]. 732 37

Vitamin B6 is considered to be a risk nutrient for elderly people. Conversion of most naturally available vitamin B6 to its functional coenzyme pyridoxal 5'-phosphate (PLP) depends on riboflavin. Therefore, interrelations were studied between riboflavin and vitamin B6 among 473 elderly people not using supplements containing B-vitamins. Habitual food consumption (assessed through dietary history with cross-check), plasma PLP levels and enzyme activities of erythrocyte glutathione reductase (EGR) and erythrocyte aspartate aminotransferase (EAST), with and without added flavin adenine dinucleotide and PLP, respectively, were determined. The results showed that unstimulated and stimulated EAST activity was higher when EGR activity (both simulated and unstimulated) was higher. Plasma PLP was positively associated with (un)stimulated EGR activities, but these correlations were not significant, probably due to the lower number of observations. Adjusted for the intake of vitamin B6 similar observations were made for the forementioned interactions between the biochemical indicators. To identify the strongest correlates of the vitamin B6 status indicators, stepwise regression analysis was carried out. The results showed that in each model an indicator of the riboflavin status was included. Our findings suggest an interaction between the status of riboflavin and vitamin B6 at intake levels normally found among Dutch elderly people.
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PMID:Interrelationships between riboflavin and vitamin B6 among elderly people (Dutch Nutrition Surveillance System). 781 35

Cisplatin, a nephrotoxic chemotherapeutic agent, was injected into Sprague Dawley rats, alone or together with cysteine, vitamin E and clonidine. The effects on erythrocyte fragility, serum composition, and kidney and liver enzymes were studied. Cisplatin was administered as two i.p. injections (6 mg/kg body weight) at an interval of 120 hours. The animals were sacrificed 24 hours after the second injection. Erythrocytes were prepared from blood collection with anticoagulant. Serum was prepared from clotted blood, collected without anticoagulant. Kidneys and liver were removed and homogenized, and a supernatant prepared by high speed centrifugation. In cisplatin-treated rats, the serum activities of aspartate aminotransferase, alanine aminotransferase, lactic dehydrogenase and alkaline phosphatase were significantly decreased, whereas the activities of isocitric dehydrogenase and glutathione reductase were increased. Also, concentrations of blood urea nitrogen, creatinine, total lipids and magnesium increased while albumin and glucose decreased. Mean osmotic fragility of erythrocytes from cisplatin-treated rats was decreased, while the haematocrit was increased. In the liver, the only change seen was an increased activity of isocitric dehydrogenase. Much greater changes were found in the kidneys, with increased activity of glucose-6-phosphate dehydrogenase and decreased activities of aspartate and alanine aminotransferases, alkaline phosphatase, malic dehydrogenase, sorbitol dehydrogenase and gamma-glutamyltransferase, as well as a decreased phosphorylation to oxidation ratio in the mitochondria, indicating reduced adenosine triphosphate production. Administration of cysteine and vitamin E together with cisplatin partially reversed the uraemia and many of the biochemical changes induced by cisplatin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Changes in serum, liver and kidneys of cisplatin-treated rats; effects of antioxidants. 788 81

The in vivo effects of human placental extract (1-4 ml/kg) on hepatic lipid peroxidation, blood and liver glutathione (GSH) levels and several enzymes associated with the antioxidant defence mechanism; i.e., catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase, together with some blood biochemical responses were investigated in rats. At an optimal dose level (4 ml/kg), a single acute intraperitoneal administration of the extract caused a significant enhancement (49.9%; p < 0.001) of lipid peroxidation with a decline in GSH level both in blood (45.1%; p < 0.001) and liver (61.0%; p < 0.001) in comparison to control animals. Activities of catalase, glutathione peroxidase and glutathione reductase were inhibited in a dose-responsive way by the treatment with the extract which also increased the activity of glutathione S-transferase in a dose-dependent manner. The extract was found to be hepatotoxic in terms of elevation of serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, serum lactate dehydrogenase and blood methemoglobin concentration. Results of this study suggest the adverse consequences of the administration of the extract due to its substantial ability to alter normal cellular processes.
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PMID:Elevated lipid peroxidation, decreased glutathione levels and changes in glutathione-related enzymes in rats treated with human placental extract. 821 15

Chloroform (CHCl3) is widely used in the manufacture of drugs, cosmetics, plastics and cleaning agents. It is also found in chlorinated drinking water. This study was designed to investigate the toxic effect of CHCl3 on isolated male rat hepatocytes using several toxicity parameters. The hepatocytes were isolated by a collagenase perfusion technique and the cell viability was determined by Trypan blue exclusion. The leakage of cytosolic enzymes such as aspartate transaminase (AST) and alanine transaminase (ALT) after treatment with CHCl3 was measured. Reduced glutathione content (GSH) and its related enzymes, glutathione reductase (GSH-Rx) and glutathione peroxidase (GSH-Px), were also evaluated to study the effect of CHCl3 on hepatocytes. Exposure to 100 and 1000 ppm CHCl3 results in a significant decrease in cell after 30 min incubation. However, the effect of 1 and 10 ppm concentrations was observed at 60 min incubation. AST leakage was significantly increased in all treatment groups, while ALT was significantly increased at 100 and 1000 ppm CHCl3 after 60 and 30 min, respectively. As early as 15 min, GSH was decreased significantly at 1000 ppm, but at 100 and 10 ppm CHCl3 the decrease in GSH began after 30 and 120 min, respectively. GSH-Px activity did not changed. However, the activity of GSH-Rx was significantly decreased at 1000 ppm CHCl3 and at the same time GSH content was decreased. The data indicate that the toxic effect of CHCl3 was dose- and time-dependent. The degree of GSH depletion correlated with increased cytotoxicity and decreased GSH-Rx activity due to CHCl3.
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PMID:The mechanism of chloroform toxicity in isolated rat hepatocytes. 835 69

Mercury is the major component of dental amalgam restorative material, which typically has 50% pure elemental mercury. It is also used in some skin creams, and in the manufacturing of plastic, drugs and fungicides. The present study was designed to investigate the toxicity of methyl mercury (MeHg+) on isolated rat hepatocytes using several toxicity parameters. The hepatocytes were isolated by a collagenase perfusion technique and were incubated with different concentrations of MeHg+ (0.1-100 ppm) for 2 h. Through the incubation period the viability was determined by Trypan blue exclusion. Reduced glutathione (GSH) content and its enzymes, glutathione peroxidase (GSH-PX) and glutathione reductase (GSH-RX) were measured. Leakage of enzymes such as aspartate transaminase (AST), and alanine transaminase (ALT) were determined. The cell viability was reduced significantly after 1 h incubation when 0.1 and 1 ppm MeHg+ were applied. The decrease in the cell viability was dose- and time-dependent. A depletion of GSH content was observed with 100 ppm MeHg+ after 30 min of incubation. A significant decrease in GSH-RX was observed with 100 ppm during 15 and 30 min of incubation, while 10 ppm of MeHg+ significantly increased ALT leakage after 60 min. However, there was a significant increase in AST leakage with 100 ppm only. The present investigation indicates that the toxic effect of MeHg+ is most likely cytosolic enzyme related.
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PMID:The mechanism of methyl mercury toxicity in isolated rat hepatocytes. 835 70

By means of a 5-week vitamin B-complex supplementation, associations between indices of vitamin B1, B2, and B6 status (activation coefficients [AC] for erythrocyte transketolase, glutathione reductase, and aspartate aminotransferase) and exercise-induced blood lactate concentration were studied. Subjects, 42 physically active college students (18-32 yrs), were randomized into vitamin (n = 22) and placebo (n = 20) groups. Before the supplementation there were no differences in ACs or basal enzyme activities between the groups. The ACs were relatively high, suggesting marginal vitamin status. In the vitamin group, all three ACs were lower (p < 0.0001) after supplementation: transketolase decreased from 1.16 (1.14-1.18) (mean and 95% confidence interval) to 1.08 (1.06-1.10); glutathione reductase decreased from 1.33 (1.28-1.39) to 1.14 (1.11-1.17); and aspartate aminotransferase decreased from 2.04 (1.94-2.14) to 1.73 (1.67-1.80). No changes were found after placebo. Despite improved indices of vitamin status, supplementation did not affect exercise-induced blood lactate concentration. Hence no association was found between ACs and blood lactate. It seems that marginally high ACs do not necessarily predict altered lactate metabolism.
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PMID:Lack of association between indices of vitamin B1, B2, and B6 status and exercise-induced blood lactate in young adults. 850 94

In order to assess the nutritional status of riboflavin and pyridoxine during pregnancy, 24 Mexican women were studied during the second trimester and 17 during the third trimester of gestation. The biochemical evaluation of the riboflavin and pyridoxine status was performed by measuring the activation coefficients (AC) of the erythrocyte glutathione reductase (eGR) and aspartate aminotransferase (eAAT), respectively. Dietary protein, riboflavin, thiamin, and calcium intake decreased significantly in the last trimester of gestation. The women presented biochemical deficiency of pyridoxine in the second and third trimester of pregnancy, but they developed biochemical deficiency of riboflavin and pyridoxine deficiency. None showed clinical signs of vitamin deficiency. No significant correlation was found between individual serum concentrations of estradiol or progesterone and eGR-AC or eAAT-AC in both trimesters of pregnancy. Six newborns studied showed normal eGR-AC and eAAT-AC.
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PMID:Riboflavin and pyridoxine status in a group of pregnant Mexican women. 869 64

The role of oxidative stress as a mechanism of hepatic injury caused by isoniazid (INH) was investigated in young growing rats. The interaction of moderate and severe degree of protein-energy malnutrition (PEM) was also investigated. Hepatic injury was produced by giving 50 mg/kg/day of INH for 2 weeks. Liver showed kupffer cell hyperplasia along with patchy sinusoidal congestion in hematoxylin (H) and eosin (E) staining. However, diffuse microglobules of oil red O' positive fat globules could be demonstrated in frozen sections stained with oil red O'. The concomitant elevation of serum ALT/AST added support to the histopathologic injury. Electronmicroscopic analysis revealed the proliferation of rough endoplasmic reticulum in INH-treated groups. The glutathione and related thiols were decreased significantly by INH both in blood and liver tissues, indicating a decrease in protective mechanism. Glutathione reductase activity was elevated concomitantly in both the tissues. A significant decrease in the activity of glutathione peroxidase and catalase is again indicative of diminished capacity to handle the disposal of hydrogen peroxide (H2O2) and lipid peroxides. All these alterations indicated that the damage to the liver cell could well be operating through the inefficient disposal of superoxides (O-2) and H2O2. A profound decrease in the protective mechanism further aggravated the picture in moderate and severe PEM, which was observed with INH alone.
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PMID:Study of oxidative stress in isoniazid-induced hepatic injury in young rats with and without protein-energy malnutrition. 902 73


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