Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P17174 (aspartate aminotransferase)
 14,872 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. In confirmation of previous work, administration of d(+)-galactosamine (0.5-0.75g/kg body wt.) to rats caused a hepatitis with histological evidence of liver damage and a 9-fold rise in aspartate aminotransferase activity in serum. 2. There was a significant elevation of blood lactate and pyruvate concentrations in 24h-starved rats treated with galactosamine but no change in the [lactate]/[pyruvate] ratio. 3-Hydroxybutyrate and acetoacetate concentrations in blood were decreased. 3. The changes in the concentrations of lactate, pyruvate and ketone bodies in the freeze-clamped liver were parallel to those observed in the blood. 4. In the livers of 24h-starved galactosamine-treated rats there were large increases in the concentrations of alanine (3-fold), citrate (5-fold), 2-oxoglutarate (4-fold), with smaller increases in malate, glutamate and aspartate. There was a 4-fold rise in the value of the mass-action ratio of the alanine aminotransferase system in the livers of galactosamine-treated rats when compared to controls. 5. There was a significant decrease in the activities of aspartate and alanine aminotransferases in the cytoplasm and the soluble fraction of sonicated homogenates of the livers of rats treated with galactosamine. The activity of phosphoenolpyruvate carboxylase was decreased by 75% of the control value. 6. Glucose synthesis from lactate in perfused livers from galactosamine-treated rats was inhibited 39% when compared with controls. 7. The results indicate that the conversion of lactate into glucose is decreased in the livers of galactosamine-treated rats and that this decrease may be due to the loss of phosphoenolpyruvate carboxylase from damaged hepatocytes.
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PMID:Metabolic studies in experimental liver disease resulting from D(+)-galactosamine administration. 465 44

14C-labeled bicarbonate was incorporated into trichloroacetic acid-insoluble material by cell suspensions of A. viscosus strain M100 and also into the four-carbon fermentation product, succinate, but not into the three-carbon fermentation product, lactate. The initial step in the conversion of 14C-labeled bicarbonate into both trichloroacetic acid-insoluble material and succinate was catalyzed by the enzyme phosphoenolypyruvate carboxylase, which served to convert the glycolytic intermediate, phosphoenolpyruvate, and bicarbonate to the four-carbon compound, oxalacetate. The metabolic fate of oxalacetate was its conversion to either trichloroacetic acid-insoluble material or succinate. One pathway by which oxalacetate may be metabolized into acid-insoluble material is via its conversion to the biosynthetic precursor aspartate by the action of glutamate aspartate aminotransferase. One source of the alpha-amino group of aspartate was the ammonium ion, which could be incorporated into glutamate, the substrate of the glutamate aspartate aminotransferase reaction, by the action of a reduced nicotinamide adenine dinucleotide phosphate-dependent glutamate dehydrogenase whose reducing equivalents could be derived from the nicotinamide adenine dinucleotide phosphate-dependent oxidative reactions of the hexose monophosphate pathway catalyzed by glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. Alternatively, oxalacetate was converted to the fermentation product, succinate, through the sequential action of malate dehydrogenase, fumarase, and succinic dehydrogenase. The resolution and partial purification of phosphoenolpyruvate carboxylase, glutamate aspartate aminotransferase, glutamate dehydrogenase, malate dehydrogenase, fumarase, and succinic dehydrogenase are also reported.
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PMID:Carbon dioxide metabolism by Actinomyces viscosus: pathways for succinate and aspartate production. 676 22

The effects of a high fat diet (30% (w/w) corn oil) on chronic streptozotocin-diabetic rats were investigated at the whole body level and at the enzyme level. The diet caused significant decreases in the extent of polydipsia (66% decrease), polyphagia (49%), polyuria (67%) and glycosuria (70%). The activities of selected hepatic enzymes from the glycolytic, gluconeogenic, ureogenic and lipogenic clusters were determined. The fat diet caused significant decreases (range: 47 to 54%) in the activity of the ureogenic enzymes carbamyl phosphate synthetase, ornithine transcarbamylase and arginase; had no effect on the glycolytic enzymes glucokinase, hexokinase and pyruvate kinase; partially decreased the diabetes-induced elevated activities of the gluconeogenic enzymes phosphoenolpyruvate carboxykinase (63% decrease), serine dehydratase (90%), alanine aminotransferase (31%) and aspartate aminotransferase (65%), and partially reversed the activity of one lipogenic enzyme, ATP citrate lyase.
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PMID:The effects of a high fat diet on chronic streptozotocin-diabetic rats. 692 68

The effect of 90% jejunoileal bypass procedure on liver enzymes was evaluated in 11 obese Zucker fat rats after a 50% weight loss. Control tissues were also collected from 11 unoperated obese rats. In the jejunoileal bypass group, there was a significant decrease in phosphofructokinase, pyruvate kinase, and glucose-6-phosphate dehydrogenase activities. Pyruvate carboxylase, alanine aminotransferase, and lactate dehydrogenase activities were not altered. Fructose 1,6-biphosphatase, aldolase, aspartate aminotransferase, and phosphoenolpyruvate carboxykinase activities were increased in the jejunoileal bypass group. These studies suggest that after jejunoileal bypass glycolysis is reduced and gluconeogenesis is increased. Amino acids may provide an essential energy source for hepatic function.
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PMID:Changes in hepatic carbohydrate metabolism after jejunoileal bypass. 707 18

The activity of enzymes with a regulatory function in the pathways of glycolysis, glyconeogenesis and NADP-generation, and the tissue content of DNA, protein, glycogen, triglycerides (TG), phospholipids (PL), cholesterol and dry matter were investigated in placentas from deliveries accompanied by fetal distress as a result of umbilical cord compression or placental dysfunction in toxemic pregnancies. In placentas from cases of fetal distress due to umbilical cord compression, there was increased activity of pyruvate kinase, 6-phosphogluconate dehydrogenase and NADP-malate dehydrogenase, and decreased activity of phosphoenolpyruvate carboxylase. The activity of aspartate aminotransferase was unchanged, and that of glucose-6-phosphate dehydrogenase was slightly elevated. The tissue content of dry matter, DNA, TG and PL was increased, whereas the protein, cholesterol and glycogen concentrations remained unaltered. In placentas from deliveries accompanied by fetal distress due to placental dysfunction, pyruvate kinase, when calculated per mg protein, was the only enzyme with decreased activity. TG, PL, glycogen and dry matter content were increased, DNA concentration was decreased, and protein and cholesterol remained unchanged. It is suggested that the divergent placental metabolic patterns found in the two fetal distress groups are related to the different levels of disturbed oxygen passage along the uterus-placenta-fetus axis.
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PMID:The placenta in intrauterine fetal deprivation. II. Biochemical profile of placentas from deliveries associated with fetal distress. 735 17

The activity and some kinetic parameters of the key enzymes of the glycolysis, the gluconeogenesis and the amino acid catabolism from the liver of male and female mink have been determined and compared to the corresponding activities from rat and cat. The activities of glucose-6-phosphatase and pyruvate kinase are dependent on sex, both being higher in females. Except for pyruvate carboxylase the glycolytic and the gluconeogenic enzyme activities of the mink are higher than those of rat and cat; especially the activities of phosphoenolpyruvate carboxykinase and glucose-6-phosphatase are markedly higher. The activities of glutamate dehydrogenase and glutamate oxaloacetate transaminase are smaller than the corresponding activities of rat but higher than those of cat. The results suggest that mink has a high capacity for gluconeogenesis compared to rat.
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PMID:Activities of carbohydrate and amino acid metabolizing enzymes from liver of mink (Mustela vison) and preliminary observations on steady state kinetics of the enzymes. 758 47

Panicum miliaceum has at least three isozymes of aspartate aminotransferase (AspAT); the cytosolic and mitochondrial isozymes (cAspAT and mAspAT) are major components and the third is a minor isozyme. Fractionation of leaf subcellular components showed that the minor isozyme was localized in plastids (pAspAT). We purified the three isozymes from green leaves of P. miliaceum. Both cAspAT and pAspAT consisted of triple subforms having the same molecular size but different isoelectric points. No substantial difference in enzymatic properties was observed among these isozymes besides the pH profiles. We isolated a full-length cDNA clone for pAspAT. This clone contains an open reading frame that encodes 457 amino acids. The amino-terminal region of the pAspAT precursor shares common features of plastid transit peptides. The amino acid sequence of P. miliaceum pAspAT shows higher similarity with other plant pAspATs than P. miliaceum cAspAT and mAspAT. The mRNA levels of the three isozymes were high in leaves compared with roots and mesocotyls. The three isozymes showed different expression patterns against environmental stimuli such as light and nitrate. The activities and protein levels of cAspAT and mAspAT increased during greening in accordance with those of phosphoenolpyruvate carboxylase and NAD-malic enzyme involved in the C4 pathway, primarily as a consequence of the increase in the levels of their mRNAs. By contrast, pAspAT was constitutively expressed during greening. The activity and protein levels of cAspAT and mAspAT selectively increased during recovery from an nitrogen deficit, primarily as a consequence of increase in the levels of their mRNAs while those of pAspAT remained unchanged.
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PMID:Aspartate aminotransferase isozymes in Panicum miliaceum L., an NAD-malic enzyme-type C4 plant: comparison of enzymatic properties primary structures, and expression patterns. 773 57

Triiodothyronine (T3) treatment of pregnant rats for 6 days, 10 micrograms/100 g, resulted in a pronounced induction of enzymes related to gluconeogenesis and lipogenesis and of mitochondrial FAD-glycerophosphate dehydrogenase in the maternal liver, as previously observed in male rats. There was virtually no change in the activity of these enzymes in the placenta. However, there was a distinct induction of these enzymes in the fetal liver, even if increments in fetal serum and liver T3 were much smaller than on the maternal side. This indicates that changes in hepatic enzyme activities are a more sensitive index of fetal hyperthyroidism than T3 levels. The increased lipogenic capacity was expressed by greater incorporation of a tritium tracer into fatty acids. Administration of triamcinolone, 2 mg/100 g, for the last 5 days of gestation resulted in marked induction of maternal hepatic enzymes of lipogenesis, gluconeogenesis and of aspartate aminotransferase (ASAT), known to occur in male rats, as well as in a metabolic pattern of insulin resistance. The response of placental enzymes was limited to a small elevation in ASAT and phosphoenolpyruvate carboxykinase (PEPCK) activity. In the fetal liver there was no stimulation of lipogenic enzymes, but a marked induction of PEPCK and ASAT. The changes in the lipogenic capacity were confirmed by tritium incorporation into serum and liver fatty acids. These results demonstrate the marked sensitivity of specific fetal enzyme systems to the maternal iatrogenic hyperthyroidism or hypercorticism. The limited alterations in placental enzyme activities are in accord with the concept that placental metabolic stability fulfils a protective function toward the fetus.
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PMID:Modulation of fetal and placental metabolic pathways in response to maternal thyroid and glucocorticoid hormone excess. 813 95

The effects of cortisol on hepatic and renal gluconeogenic enzyme activities were investigated in sheep fetuses during late gestation and after experimental manipulation of plasma cortisol levels by fetal adrenalectomy and exogenous infusion of cortisol. Hepatic and renal gluconeogenic enzyme activities increased with increasing gestational age in parallel with the normal rise in fetal cortisol levels towards term (146 +/- 2 days). For the majority of enzymes this increase in activity towards term was prevented when the prepartum cortisol surge was abolished by fetal adrenalectomy and stimulated prematurely in fetuses younger than 130 days by exogenous infusion of cortisol. When the data from all the fetuses were combined irrespective of treatment or gestational age, there were significant positive correlations between the log plasma cortisol concentration in utero and the activities of glucose-6-phosphatase, fructose diphosphatase, phosphoenolpyruvate carboxykinase and aspartate transaminase in the fetal liver and kidney, and pyruvate carboxylase in the fetal liver but not in the kidney. No correlation was observed between log plasma cortisol and alanine aminotransferase activity in either fetal liver or kidney. These findings show that cortisol is a physiological regulator of most of the fetal gluconeogenic enzymes and enhances the glucogenic capacity of the sheep fetus during late gestation.
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PMID:The effects of cortisol on hepatic and renal gluconeogenic enzyme activities in the sheep fetus during late gestation. 832 49

Sea raven (Hemitripterus americanus) given intraperitoneal implants of coconut oil containing cortisol (50 mg kg-1) and sampled 5 days later had plasma cortisol, glucose and urea concentrations higher than in a sham-implanted group. No differences in plasma ammonia, free amino acid or fatty acid concentrations were apparent between the cortisol- and sham-treated groups. There was no change in hepatic glycogen content, whereas glutamine synthetase, allantoicase, arginase, aspartate aminotransferase, tyrosine aminotransferase, alanine aminotransferase, glutamate dehydrogenase, phosphoenolpyruvate carboxykinase and 3-hydroxyacyl-coenzyme A dehydrogenase activities were higher in the cortisol-treated fish liver compared with the sham-implanted fish. On the basis of these general increases in enzyme activities, our results suggest that cortisol stimulates nitrogen metabolism in the sea raven. Amino acid catabolism may be a major source of substrate for gluconeogenesis and/or oxidation, while fatty acid mobilization may provide the fuel for endogenous use by the liver in cortisol-treated sea raven. These results further support the hypothesis that cortisol plays a role in the regulation of glucose production in stressed fish.
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PMID:Metabolic effects of cortisol treatment in a marine teleost, the sea raven 931 10


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