Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.4.1.2 (glutamate dehydrogenase)
 4,380 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Olfactory bulb removal and consequential degeneration of the lateral olfactory tract led to a decrease in the levels of glutaminase and malate dehydrogenase in the ipsilateral olfactory cortex. These changes in enzyme activity may account for the well established decrease in the levels of aspartate and glutamate in the olfactory cortex following ipsilateral bulbectomy. The level of glutamine synthetase, a glial marker enzyme, was slightly increased while the activities of glutamate decarboxylase, glutamate dehydrogenase, and glutamate oxaloacetic transaminase were unchanged.
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PMID:Effect of lesions of the olfactory bulb on the levels of amino acids and related enzymes in the olfactory cortex of the guinea pig. 614 31

Addition of phenylephrine to isolated perfused rat liver is followed by an increased 14CO2 production from [1-14C]glutamate, [1-14C]glutamine, [U-14C]proline and [3-14C]pyruvate, but by a decreased 14CO2 production from [1-14C]pyruvate. Simultaneously, there is a considerable decrease in tissue content of 2-oxoglutarate, glutamate and citrate. Stimulation of 14CO2 production from [1-14C]glutamate is also observed in the presence of amino-oxyacetate, suggesting a stimulation of glutamate dehydrogenase and 2-oxoglutarate dehydrogenase fluxes by phenylephrine. Inhibition of pyruvate dehydrogenase flux by phenylephrine is due to an increased 2-oxoglutarate dehydroxygenase flux. Phenylephrine stimulates glutaminase flux and inhibits glutamine synthetase flux to a similar extent, resulting in an increased hepatic glutamine uptake. Whereas the effects of NH4+ ions and phenylephrine on glutaminase flux were additive, activation of glutaminase by glucagon was considerably diminished in the presence of phenylephrine. The reported effects are largely overcome by prazosin, indicating the involvement of alpha-adrenergic receptors in the action of phenylephrine. It is concluded that stimulation of gluconeogenesis from various amino acids by phenylephrine is due to an increased flux through glutamate dehydrogenase and the citric acid cycle.
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PMID:Effect of phenylephrine on glutamate and glutamine metabolism in isolated perfused rat liver. 614 74

The accumulations by axoplasmic transport of selected enzyme activities proximal and distal to a ligature placed on the sciatic nerve were monitored in rats exposed in utero to maternal antibodies to nerve growth factor (NGF) and in control rats. Littermates of the animals exposed to anti-NGF were shown elsewhere to have had a 70% reduction in the number of sensory neurons in dorsal root ganglia and a 90% reduction in number of neurons in superior cervical (sympathetic) ganglion. The accumulation of F(-)-sensitive acid phosphatase activity was depressed 75% both proximal and distal to the tie. Accumulation of F(-)-resistant acid phosphatase activity was depressed nearly 50% proximal to the tie. Distal accumulation of this activity did not occur in either group of rats. Accumulation of acetylcholinesterase activity was depressed 30%. Distal accumulation of the activities of beta-glucuronidase and hexokinase was depressed 50%. In the lumbar dorsal root ganglia, dry weight was reduced 40%, and the activities of peroxide-sensitive, F(-)-resistant acid phosphatase and of the mitochondrial enzymes hexokinase, glutamic dehydrogenase, glutamic-oxalacetic transaminase, and NAD-dependent isocitric dehydrogenase were all reduced a little more, 45--50% per ganglion. However, the activities of the lysosomal enzymes, F(-)-sensitive acid phosphatase and beta-glucuronidase, of the peroxide-resistant, F(-)-resistant acid phosphatase, and of the mitochondrial enzyme glutaminase were all reduced about 60% per ganglion. The results of these measurements were interpreted to suggest that much, and perhaps all, of the F(-)-sensitive acid phosphatase activity in motion in peripheral nerve in rat is confined to sensory axons.
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PMID:Transported enzymes in sciatic nerve and sensory ganglia of rats exposed to maternal antibodies against nerve growth factor. 616 7

The metabolism of glucose and glutamine in freshly prepared resting and concanavalin A-stimulated rat thymocytes was studied. Concanavalin A addition enhanced uptake of both glucose and glutamine and led to an increase in oxidative degradation of both substrates to CO2. With variously labelled [14C]glucose, it was shown that the pathways of glucose dissimilation were equally stimulated by the mitogen. A disproportionately large percentage of the extra glucose taken up was converted into lactate, but concanavalin A also caused an increase in the oxidation of pyruvate as judged by the enhanced release of 14CO2 from [2-14C]-, [3,4-14C]- and [6-14C]-glucose. Addition of glutamine did not affect glucose metabolism. The major end products of glutamine metabolism by resting and mitogen-stimulated rat thymocytes were glutamate, aspartate, CO2 and NH3. Virtually no lactate was formed from glutamine. Concanavalin A enhanced the formation of all end products except glutamate, indicating that more glutamine was metabolized beyond the stage of glutamate in the mitogen-activated cells. Addition of glucose caused a significant decrease in the rates of glutamine utilization and conversion into aspartate and CO2 in the absence and in the presence of concanavalin A. In the presence of glucose, almost all nitrogen of the metabolized glutamine was accounted for as NH3 released via the glutaminase and/or glutamate dehydrogenase reactions. In the absence of glucose, part (18%) of the glutamine nitrogen was metabolized by the resting and to a larger extent (38%) by the mitogen-stimulated thymocytes via a transaminase or amidotransferase reaction.
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PMID:Glucose and glutamine metabolism in rat thymocytes. 633 20

The role of mitochondrial swelling in renal ammoniagenesis was studied by the administration of 10 mg.kg-1 2,4-dinitrophenol, in vivo, to normal and chronically acidotic rats. 2,4-Dinitrophenol increased ammonia excretion in in vivo and in vitro production from glutamine by renal cortical slices and isolated kidneys perfused with 1 mM L-glutamine. Ammonia production per glutamine molecule utilized rose towards 2, consistent with activation of the mitochondrial glutaminase-glutamate dehydrogenase pathway in 2,4-dinitrophenol-treated and acidotic rats. The rank order of 2,4-dinitrophenol stimulation of ammonia formation in vivo and in vitro was normal less than normal + 2,4-dinitrophenol less than acidotic less than acidotic + 2,4-dinitrophenol. 2,4-Dinitrophenol administration appears to enlarge the in situ proximal tubule mitochondrial population and to increase the number undergoing degradation, suggesting that mitochondrial alterations correlate with ammoniagenesis in vivo.
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PMID:2,4-dinitrophenol stimulation of renal ammoniagenesis. 707 39

Rainbow trout acclimatized to 9 degrees C were subjected to a temperature increase (up to 17 degrees C) for 16 hrs. During the period of acclimatization to 17 degrees C, we studied blood ammonia and urea and the hepatic activity of glutamate dehydrogenase, glutaminase, uricase and arginase. The daily mean rates of blood ammonia and urea did not differ significantly at 9 and 17 degrees C. However, the pattern of these two parameters during the circadian cycle was not the same at 9 degrees C as after 23 days at 17 degrees C. The enzymatic activities rose after one day at 17 degrees C and remained unchanged, except for arginase which showed perfect thermal compensation. During the circadian cycle, there was some similitude between glutaminase activity and blood ammonia at 9 degrees C and after 23 days at 17 degrees C, as well as between arginase activity and blood urea.
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PMID:[Effect of temperature increase on some aspects of nitrogen catabolism in rainbow trout (Salmo gairdneri Rich.)]. 715 5

1. The maximum activity of hexokinase in lymphocytes is similar to that of 6-phosphofructokinase, but considerably greater than that of phosphorylase, suggesting that glucose rather than glycogen is the major carbohydrate fuel for these cells. Starvation increased slightly the activities of some of the glycolytic enzymes. A local immunological challenge in vivo (a graft-versus-host reaction) increased the activities of hexokinase, 6-phosphofructokinase, pyruvate kinase and lactate dehydrogenase, confirming the importance of the glycolytic pathway in cell division. 2. The activities of the ketone-body-utilizing enzymes were lower than those of hexokinase or 6-phosphofructokinase, unlike in muscle and brain, and were not affected by starvation. It is suggested that the ketone bodies will not provide a quantitatively important alternative fuel to glucose in lymphocytes. 3. Of the enzymes of the tricarboxylic acid cycle whose activities were measured, that of oxoglutarate dehydrogenase was the lowest, yet its activity (about 4.0mumol/min per g dry wt. at 37 degrees C) was considerably greater than the flux through the cycle (0.5mumol/min per g calculated from oxygen consumption by incubated lymphocytes). The activity was decreased by starvation, but that of citrate synthase was increased by the local immunological challenge in vivo. It is suggested that the rate of the cycle would increase towards the capacity indicated by oxoglutarate dehydrogenase in proliferating lymphocytes. 4. Enzymes possibly involved in the pathway of glutamine oxidation were measured in lymphocytes, which suggests that an aminotransferase reaction(s) (probably aspartate aminotransferase) is important in the conversion of glutamate into oxoglutarate rather than glutamate dehydrogenase, and that the maximum activity of glutaminase is markedly in excess of the rate of glutamine utilization by incubated lymphocytes. The activity of glutaminase is increased by both starvation and the local immunological challenge in vivo. This last finding suggests that metabolism of glutamine via glutaminase is important in proliferating lymphocytes.
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PMID:Maximum activities of some enzymes of glycolysis, the tricarboxylic acid cycle and ketone-body and glutamine utilization pathways in lymphocytes of the rat. 716 29

The effect of chronic acid feeding and its subsequent withdrawal was determined on the amounts of the metabolic intermediates and enzymic activities of the purine nucleotide cycle. Sprague-Dawley rats were given 1.5% (w/v) NH4Cl in their drinking water for 5 days. The renal excretion of NH3 rose 70-fold and the rats developed acidosis. The amount of renal IMP rose from a control value of 4.5 +/- 2.2 to 20.4 +/- 3.7nmol/g of kidney after 48h of acid feeding (P less than 0.001) and fell to normal within 48h of the recovery. Adenylosuccinate concentrations fell from a control value of 4.5 +/- 0.9nmol/g of kidney to 1.2 +/- 0.3nmol/g (P less than 0.005) by day 5 of acidosis and continued to fall to undetectable values by 48h after recovery. The amount of AMP remained constant through the acid-feeding and the recovery periods. The activity of adenylosuccinate synthetase, the rate-limiting enzyme of the purine nucleotide cycle, paralleled the rise and fall in NH3 excretion. The activities of phosphate-dependent glutaminase and glutamate dehydrogenase were elevated during the acid-feeding and the recovery period. Thus changes in the purine nucleotide cycle correlate with changes in NH3 excretion to a more parallel degree than does the activity of glutaminase or glutamate dehydrogenase.
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PMID:The purine nucleotide cycle in the regulation of ammoniagenesis during induction and cessation of chronic acidosis in the rat kidney. 730 74

Metabolite content was determined in freeze-clamped kidneys to elucidate the rate-controlling steps which are responsible for the inhibition of renal ammoniagenesis that occurs when rats are allowed to recover from metabolic acidosis. After 1 day of recovery from acidosis there were increased renal contents of glutamate, glutamine, alpha-ketoglutarate, citrate, lactate, and malate. The calculated cytoplasmic concentration of oxaloacetate was also increased. The renal content of phosphoenolpyruvate, 3-phosphoglycerate, and ammonia decreased during recovery. No changes were observed in the renal content of the adenine nucleotides or of inorganic phosphate. The activities of phosphate-dependent glutaminase and glutamate dehydrogenase were elevated even after 7 days of recovery although the renal contents of glutamate and alpha-ketoglutarate had returned to control levels by this time. The changes in oxaloacetate and phosphoenolpyruvate are consistent with the fall in the activity of phosphoenolpyruvate carboxykinase observed by Parry and Brosnan. The increased levels of alpha-ketoglutarate and of glutamate are considered to be a consequence of a primary change in the activity of alpha-ketoglutarate dehydrogenase. These results are discussed in the light of the known effects of these metabolites on glutaminase activity and on glutamine entry into renal mitochondria.
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PMID:Renal metabolite concentrations and the activities of glutaminase and glutamate dehydrogenase during recovery from metabolic acidosis in the rat. 733 66

The activity of glutaminase per milligram of protein increased threefold after cultured human diploid fibroblasts were subcultured in fresh medium. The maximum activity was reached after 2 days of growth and decreased once the cells reached confluency. The increase of glutaminase activity was independent of the glutamine concentration between 0.2 and 2.0 mmol/l. In contrast, the specific activity of glutamate dehydrogenase was independent both of the glutamine concentration and the growth phase of the cultured cells. These results indicate that glutaminase, the first enzyme involved in the ultilization of glutamine as an energy source, is elevated in rapidly dividing human diploid fibroblasts.
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PMID:Increase in glutaminase activity during the growth cycle of cultured human diploid fibroblasts. 737 73


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