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At least 1,099 records · Page 61Linked to original sources
PubMed1983

Glutamic-oxalacetic transaminase (SGOT) and glutamic-pyruvic transaminase (SGPT) in newborns in relation to the gestational age.

The transaminase enzymatic activity (SGOT-SGPT) was measured in the first 72h. of life, within the 7th day and on the 30th day of life in two groups of new borns i.e. full-term and premature ones with a gestational age less than or equal to 37 weeks. The premature babies were divided into two sub-groups: babies with a gestational ager less than or equal to 32 and greater than 32 weeks. Our results on the SGOT and SGPT activity in healthy full-term newborns agree with literature data, but indicate a lowering of the SGOT mean values at the 30th day of life. A similar lowering occurs at the 7th day of life; in premature newborns; these have lower SGOT values during the first 72h. of life than full-term newborns. Newborns with a gestational age of less than or equal to 32 weeks have higher SGOT values than newborns with a gestational age of greater than 32 weeks. The mean values of SGPT during the first days of life are higher in full-term than in premature newborns; there are no significant differences in the sub groups with different gestational age.

Aging↗
PubMed1982

The serum glutamic oxaloacetic transaminase/serum glutamic pyruvic transaminase ratio as a prognostic index in severe acute viral hepatitis.

The SGOT/SGPT ratio was studied in 25 patients with severe acute viral hepatitis due to either B or non A-non B hepatitis. The transaminase levels were performed within 10 days of onset of the hepatitis or within 4 days of the diagnosis of fulminant hepatic failure. Twelve patients died of their acute illness. There was a significant difference between the SGOT/SGPT ratios of females who died mean = 2.05) and lived (mean 0.45) (p less than 0.001) and between the SGOT/SGPT ratios of males who died (mean - 1.01) and lived (mean 0.45) (p less than 0.02). Using 95% confidence intervals the expected ratios for combined sexes were calculated to be 0.31 to 0.63 for survivors and from 1.20 to 2.26 for nonsurvivors. Neither age not viral etiology affected the prognosis in this study.

Acute Disease↗
PubMed1997

[Glutamate oxalacetate and glutamate pyruvate aminotransferase activity in Streptomyces hygroscopicus 155 producing antibiotic complex].

Antibiotic activity, aminotransferase activity and composition of intracellular amino acids in low and high potent variants of Streptomyces hygroscopicus 155 were studied. The data of the study are indicative of some general regularities characteristic of amino acid metabolism in actinomycetes: an increased pool of the main aminodonor amino acids (alanine, asparaginic and glutaminic acids) and an increased activity of aminotransferases in the cultures of both the variants when grown in media with readily assimilable nitrogen sources.

Alanine↗
PubMed1999

Glutamate in synaptic terminals is reduced by lack of glucose but not hypoxia in rat hippocampal slices.

Although excessive release of the neurotransmitter glutamate contributes to ischemic neuronal damage, immunocytochemical studies have not found a loss of glutamate from ischemic axon terminals. We examined the effects of two components of ischemia, hypoxia and hypoglycemia, on glutamate loss from rat hippocampal slices. In vitro hypoglycemia induced by incubation for 1 h without glucose depleted 50% of glutamate from slices when ATP levels were about 5 nmol/mg protein. Hypoxic slices aerated with N2 reached similar ATP levels without significant glutamate depletion. To induce 50% glutamate losses with chemical hypoxia, ATP had to be depleted to < 1 nmol/mg protein. Immunocytochemical staining indicated that glutamate-like immunoreactivity was reduced throughout slices by hypoglycemia. Hypoxia decreased glutamate-like immunoreactivity in neuronal perikarya and dendrites of pyramidal cells and granule cells. However, in contrast to hypoglycemia, hypoxia maintained or increased glutamate-like immunoreactivity in many terminals. Hypoxia and hypoglycemia induced similar, ATP-dependent releases of glutamate into supernatants, which could account for only part of the hypoglycemic losses. The additional hypoglycemic losses were consistent with increased catabolism of glutamate. Glutamate losses from hypoglycemic terminals were reduced by blockade of aspartate aminotransferase or the tricarboxylic acid cycle. Exogenous glutamate increased glutamate in hypoglycemic slices to hypoxic levels and returned glutamate-like immunoreactivity to terminals, suggesting that terminals maintained glutamate uptake during metabolic insults. Hypoglycemia induces a large loss of glutamate that does not occur during hypoxia. The greater loss of glutamate from terminals during hypoglycemia is consistent with increased metabolism of glutamate via aspartate aminotransferase and not increased release of glutamate. Continued uptake of glutamate by hypoxic terminals may help to maintain their levels of glutamate. Hypoglycemic metabolism of glutamate may decrease pathologic glutamate release and contribute to the prolonged neurologic abnormalities associated with recovery from hypoglycemia.

Adenosine Triphosphate↗
PubMed1993

Vulnerability of oligodendroglia to glutamate: pharmacology, mechanisms, and prevention.

Periventricular white matter injury, the principal variety of brain injury of the human premature infant, involves differentiating oligodendroglia. Nothing is known of the biochemical mechanism of oligodendroglial death in this disorder. Because an early event in periventricular white matter injury is ischemia-induced axonal disruption and because such axonal destruction could lead to a marked increase in local concentrations of glutamate, we evaluated the vulnerability of differentiating oligodendroglia to glutamate in a culture model. Oligodendroglia were isolated from mixed-glial primary cultures by a selective detachment technique and grown in a primary culture under conditions that lead to differentiation. These oligodendroglia were found to be highly vulnerable to glutamate-induced cell death. The EC50 for glutamate for a 24 hr exposure was approximately 200 microM, comparable to the value reported for neurons in conventional cerebral cortical cultures. Astrocytes, in contrast, were shown to be resistant to as much as 5 mM glutamate. Study of glutamate receptor antagonists and glutamate transport substrates showed that the glutamate-induced oligodendroglial death was not related to a receptor mechanism, as operates in neurons, but rather was secondary to glutamate uptake by the oligodendroglia. Glutamate transport by high-affinity, sodium-dependent and by sodium-independent systems was shown. The central importance of glutamate uptake for the toxic effect of glutamate was shown by total prevention of the oligodendroglial toxicity by the simultaneous inhibition of glutamate uptake by the specific inhibitor D,L-threo-beta-hydroxyaspartate. Subsequent observations showed that the toxicity of glutamate was mediated by free radical attack, the consequence of glutathione depletion, apparently caused by the action of a glutamate-cystine exchange mechanism that results in cystine and thereby glutathione depletion. Thus, addition of cystine or cysteine totally prevented the glutamate toxicity to oligodendroglia. Second, glutamate exposure led to cystine efflux. Third, glutathione levels decreased markedly in cells exposed to glutamate, and this marked decrease preceded the loss of cell viability. Fourth, glutamate toxicity could be prevented totally by exposure to different free radical scavengers, vitamin E and idebenone. The data thus show that glutamate is highly toxic to oligodendroglia. Moreover, the findings raise the possibilities that such glutamate toxicity is operative in the oligodendroglial cell death associated with ischemic processes that disrupt axons, such as periventricular white matter injury of the premature infant, and that novel therapies directed against glutamate transport, glutathione depletion, and free radical attack might be beneficial in prevention of that injury.

Animals↗
PubMed1999

Evidence of metabotropic glutamate receptor subtypes found on catfish horizontal and bipolar retinal neurons.

We have used electrophysiological, pharmacological and immunological techniques to determine which classes of metabotropic glutamate receptors exist on cone horizontal cells in the catfish retina. Patch-clamp recordings in acutely dissociated cone horizontal cells provide evidence that group I and III metabotropic glutamate receptors exist, and are linked to modulation of a voltage-gated calcium current. Group II metabotropic glutamate receptor agonists did not affect the calcium current. Immunocytochemical techniques were used to study the localization of metabotropic glutamate receptor subtypes found in the catfish retina. Antibodies raised against group I (metabotropic glutamate receptor 1alpha, metabotropic glutamate receptor 5), group II (metabotropic glutamate receptor 2/3) and group III (metabotropic glutamate receptor 6) metabotropic glutamate receptor subtypes were used to label acutely dissociated horizontal, bipolar and Müller cells. Results from immunostaining provide evidence that cone horizontal cells express group I (metabotropic glutamate receptor 1alpha, metabotropic glutamate receptor 5) and group III (metabotropic glutamate receptor 6), but not group II (metabotropic glutamate receptor 2/3) receptor subtypes, consistent with our electrophysiological results. Cone horizontal cells exposed to anti-metabotropic glutamate receptor 1alpha, 5 or 6 antibodies all demonstrated diffuse overall staining, with patches of dark immunostaining found on both dendritic processes and cell somata. In catfish bipolar cells, all four of the anti-metabotropic glutamate receptor antibodies stained the processes and cell bodies of bipolar cells homogeneously. There was no evidence for a group of bipolar cells that did not stain with the antimetabotropic glutamate receptor antibodies, although the densest immunostaining occurred when bipolar cells were incubated with the anti-metabotropic glutamate receptor 6 antibody. Müller cells did not show immunostaining against any anti-metabotropic glutamate receptor antibody. Our non-immune controls confirmed that immunostaining was specific for the antigen, and immunoblots were performed to demonstrate the specificity of the antibodies in catfish retina. These results support the hypothesis that group I and III metabotropic glutamate receptor subtypes are found on catfish horizontal cells, and group I, II and III metabotropic glutamate receptor subtypes are expressed on catfish bipolar cells. The metabotropic glutamate receptors on catfish cone horizontal cells act to modulate the voltage-gated sustained calcium current found on these cells.

Animals↗
PubMed2005

Glutamate synthase: structural, mechanistic and regulatory properties, and role in the amino acid metabolism.

Ammonium ion assimilation constitutes a central metabolic pathway in many organisms, and glutamate synthase, in concert with glutamine synthetase (GS, EC 6.3.1.2), plays the primary role of ammonium ion incorporation into glutamine and glutamate. Glutamate synthase occurs in three forms that can be distinguished based on whether they use NADPH (NADPH-GOGAT, EC 1.4.1.13), NADH (NADH-GOGAT, EC 1.4.1.14) or reduced ferredoxin (Fd-GOGAT, EC 1.4.7.1) as the electron donor for the (two-electron) conversion of L-glutamine plus 2-oxoglutarate to L-glutamate. The distribution of these three forms of glutamate synthase in different tissues is quite specific to the organism in question. Gene structures have been determined for Fd-, NADH- and NADPH-dependent glutamate synthases from different organisms, as shown by searches in nucleic acid sequence data banks. Fd-glutamate synthase contains two electron-carrying prosthetic groups, the redox properties of which are discussed. A description of the ferredoxin binding by Fd-glutamate synthase is also presented. In plants, including nitrogen-fixing legumes, Fd-glutamate synthase and NADH-glutamate synthase supply glutamate during the nitrogen assimilation and translocation. The biological functions of Fd-glutamate synthase and NADH-glutamate synthase, which show a highly tissue-specific distribution pattern, are tightly related to the regulation by the light and metabolite sensing systems. Analysis of mutants and transgenic studies have provided insights into the primary individual functions of Fd-glutamate synthase and NADH-glutamate synthase. These studies also provided evidence that glutamate dehydrogenase (NADH-GDH, EC 1.4.1.2) does not represent a significant alternate route for glutamate formation in plants. Taken together, biochemical analysis and genetic and molecular data imply that Fd-glutamate synthase incorporates photorespiratory and non-photorespiratory ammonium and provides nitrogen for transport to maintain nitrogen status in plants. Fd-glutamate synthase also plays a role that is redundant, in several important aspects, to that played by NADH-glutamate synthase in ammonium assimilation and nitrogen transport.

Amino Acid Oxidoreductases↗