Maleate-Induced Stimulation of Glutamine Metabolism in Dog Renal Cortical Tubules1

2015 ◽  
pp. 36-43 ◽  
Author(s):  
A. Gougoux ◽  
P. Vinay ◽  
M. Duplain
Keyword(s):  
Glutamine Metabolism ◽  
Stimulation Of

scholarly journals Glutamine metabolism in lymphocytes of the rat

1983 ◽  
Vol 212 (3) ◽  
pp. 835-842 ◽  
Author(s):  
M S M Ardawi ◽  
E A Newsholme
Keyword(s):  
Amino Acids ◽  
Concanavalin A ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Thymidine Incorporation ◽  
Adenine Nucleotides ◽  
Glutamine Metabolism ◽  
Mesenteric Lymph Nodes ◽  
Mesenteric Lymph ◽  
End Products ◽  
Stimulation Of

The metabolism of glutamine in resting and concanavalin-A-stimulated lymphocytes was investigated. In incubated lymphocytes isolated from rat mesenteric lymph nodes, the rates of oxygen and glutamine utilization and that of aspartate production were approximately linear with respect to time for 60 min, and the concentrations of adenine nucleotides plus the ATP/ADP or ATP/AMP concentration ratios remained approximately constant for 90 min. The major end products of glutamine metabolism were glutamate, aspartate and ammonia: the carbon from glutamine may contribute about 30% to respiration. When both glucose and glutamine were presented to the cells, the rates of utilization of both substances increased. Evidence was obtained that the stimulation of glycolysis by glutamine could be due, in part, to an activation of 6-phosphofructokinase. Starvation of the donor animal increased the rate of glutamine utilization. The phosphoenolpyruvate carboxykinase inhibitor mercaptopicolinate decreased the rate of glutamine utilization by 28%; the rates of accumulation of glutamate and ammonia were decreased, whereas those of lactate, aspartate and malate were increased. The mitogen concanavalin A increased the rate of glutamine utilization (by about 51%). The rate of [3H]thymidine incorporation into DNA caused by concanavalin A in cultured lymphocytes was very low in the absence of glutamine; it was increased about 4-fold at 1 microM-glutamine and was maximal at 0.3 mM-glutamine; neither other amino acids nor ammonia could replace glutamine.

Renal ammonium production—une vue canadienne

1987 ◽  
Vol 65 (4) ◽  
pp. 489-498 ◽  
Author(s):  
J. T. Brosnan ◽  
M. Lowry ◽  
P. Vinay ◽  
A. Gougoux ◽  
M. L. Halperin
Keyword(s):  
Metabolic Acidosis ◽  
Glutamine Metabolism ◽  
Ammonium Excretion ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Balance ◽  
Ammonium Production ◽  
Alternate Fuels ◽  
Glutaminase Activity ◽  
Stimulation Of

The purpose of this review is to examine the factors regulating ammonium production in the kidney and to place these factors in the perspective of acid–base balance. Renal ammonium production and excretion are required to maintain acid–base balance. However, only a portion of renal ammonium production is specifically stimulated by metabolic acidosis. One should examine urinary ammonium excretion at three levels: distribution of ammonium between blood and urine, augmented glutamine metabolism, and an energy constraint due to ATP balance considerations. With respect to the biochemical regulation of acid–base renal ammonium production, an acute stimulation of α-ketoglutarate dehydrogenase by a fall in pH seems to be important but this may not be the entire story. In chronic metabolic acidosis augmented glutamine entry into mitochondria (dog) or increased phosphate-dependent glutaminase activity (rat) become critical to support a high flux rate. Metabolic alterations, which diminish the rate of oxidation of alternate fuels, might also be important. The above principles are discussed in the ketoacidosis of fasting, the clinically important situation of high rates of renal ammonium production.

scholarly journals The ornithine requirement of urea synthesis. Formation of ornithine from glutamine in hepatocytes

1986 ◽  
Vol 239 (3) ◽  
pp. 773-776 ◽  
Author(s):  
P Lund ◽  
D Wiggins
Keyword(s):  
Cyclic Amp ◽  
Glutamine Metabolism ◽  
Urea Synthesis ◽  
Dibutyryl Cyclic Amp ◽  
Stimulation Of

In hepatocytes, urea synthesis from glutamine is independent of added ornithine, even when rates are high after stimulation of glutamine metabolism by dibutyryl cyclic AMP, phenylephrine or vasopressin. Incubation with glutamine increases tissue [ornithine]. The increases parallel those of [N-acetylglutamate] under different conditions. The ornithine requirement of urea synthesis increases with increasing supply of ammonia. A function of the unique, highly regulated, glutaminase of liver may be to regulate ornithine synthesis.

scholarly journals Effect of phenylephrine on glutamate and glutamine metabolism in isolated perfused rat liver

1984 ◽  
Vol 221 (3) ◽  
pp. 651-658 ◽  
Author(s):  
D Häussinger ◽  
H Sies
Keyword(s):  
Glutamate Dehydrogenase ◽  
Rat Liver ◽  
Glutamine Metabolism ◽  
Isolated Perfused Rat Liver ◽  
Perfused Rat Liver ◽  
Alpha Adrenergic Receptors ◽  
14Co2 Production ◽  
Oxoglutarate Dehydrogenase ◽  
Glutamine Uptake ◽  
Stimulation Of

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.

scholarly journals Effect of hyperbaric oxygenation on metabolism of glutamine in the liver

2014 ◽  
Vol 60 (3) ◽  
pp. 364-371 ◽  
Author(s):  
P.N. Savilov
Keyword(s):  
Glutamine Synthetase ◽  
Glutamate Dehydrogenase ◽  
Hyperbaric Oxygenation ◽  
Inhibitory Effect ◽  
Glutamine Metabolism ◽  
Albino Rats ◽  
Functional Heterogeneity ◽  
Glutamine Concentration ◽  
Hyperoxic Exposure ◽  
Stimulation Of

The effect of three-day course of hyperbaric oxygenation (HBO; 3 atm, 50 min, 1 session per day) on glutamine metabolism in the liver has been investigated in 72 adult albino rats. The content of ammonia, glutamate, glutamine, activity of glutamine synthetase (GS), phosphate-dependent glutaminase (PDG), and glutamate dehydrogenase (GDH) were studied in left (LLL) and median (MLL) lobes of the liver. The course of HBO had an inhibitory effect on all the enzymes studied. Inhibitory effect of hyperoxia on GDH activity persisted up to day 11 after the course of HBO in both lobes of the liver, while decreased glutamate normalized in both lobes. Reduced glutamine concentration normalized to day 4, and the concentration of ammonia and remained elevated for 11 days after the end of hyperoxic exposure. Inhibitory effect of hyperoxia on GS activity in LLL and MLL disappeared on day 4 and day 11 day after the end of the HBO course. PDG activity reduced by HBO in both lobes normalized to the day 4 day after oxygenation; however, on day 11 it selectively decreased in LLL, where simultaneous stimulation of GS activity was also observed. The results demonstrate different sensitivity of liver GS, PDG and GDH of normal rats to the inhibitory effect of HBO. Different dynamics of GS and PDG activity in LLL and MLL of oxygenated rats suggests functional heterogeneity of the glutamine cycle in hepatocytes of liver lobes after HBO

scholarly journals Stimulation of glutamine metabolism by 3-aminopicolinate in isolated dog kidney-cortex tubules

1983 ◽  
Vol 210 (2) ◽  
pp. 483-487 ◽  
Author(s):  
D Durozard ◽  
G Baverel
Keyword(s):  
Phosphoenolpyruvate Carboxykinase ◽  
Glutamine Metabolism ◽  
Kidney Cortex ◽  
Kidney Tubules ◽  
Direct Stimulation ◽  
Dog Kidney ◽  
Glucose Synthesis ◽  
Isolated Dog Kidney ◽  
Gluconeogenic Substrates ◽  
Stimulation Of

1. The effects of 3-aminopicolinate, a known hyperglycaemic agent in the rat, on glutamine metabolism were studied in isolated dog kidney tubules. 2. 3-Aminopicolinate greatly stimulated glutamine (but not glutamate) removal and glutamate accumulation from glutamine as well as formation of ammonia, aspartate, lactate, alanine and glucose. 3. The increased accumulation of aspartate from glutamine and glutamate, and the inhibition of glucose synthesis from various non-nitrogenous gluconeogenic substrates, as well as the increased accumulation of malate from succinate, support the proposal that 3-aminopicolinate is an inhibitor rather than a stimulator of phosphoenolpyruvate carboxykinase (EC 4.1.1.32) in dog kidney tubules. 4. With glutamine as substrate, the increase in flux through glutamate dehydrogenase (EC 1.4.1.3) could not explain the large increase in glutamine removal caused by 3-aminopicolinate. 5. Inhibition by amino-oxyacetate of accumulation of aspartate and alanine from glutamine caused by 3-aminopicolinate did not prevent the acceleration of glutamine utilization. 6. These data are consistent with a direct stimulation of glutaminase (EC 3.5.1.2) by 3-aminopicolinate in dog kidney tubules.

L-glutamine with D-glucose stimulates oxidative metabolism and NaCl absorption in piglet jejunum

1992 ◽  
Vol 263 (6) ◽  
pp. G960-G966 ◽  
Author(s):  
J. M. Rhoads ◽  
E. O. Keku ◽  
J. P. Woodard ◽  
S. I. Bangdiwala ◽  
J. G. Lecce ◽  
...  
Keyword(s):  
Oxidative Metabolism ◽  
Carbonic Acid ◽  
Apical Membrane ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Glutamine Metabolism ◽  
Nacl Absorption ◽  
The Relationship ◽  
Stimulation Of

To explore the relationship between intestinal fluid absorption and oxidative metabolism, we measured the effects of amino acids and glucose on piglet jejunal ion transport and oxygen consumption (QO2) in vitro. Jejunal QO2 was stimulated by L-glutamine and D-glucose but not by the nonmetabolizable organic solutes methyl beta-D-glucoside or L-phenylalanine. QO2 was maximally enhanced by the combination of D-glucose and L-glutamine (5 mM). Even though 5 mM L-glutamine was previously found to be insufficient to stimulate NaCl absorption, 5 mM L-glutamine enhanced jejunal NaCl flux when combined with equimolar mucosal D-glucose. Either D-glucose or methyl beta-D-glucoside caused an increase in short-circuit current (Isc), an increase in Na+ absorption in excess of Isc, and a decrease in Cl- secretion, when L-glutamine was substituted for D-glucose (10 mM) on the serosal side. This relationship suggests that mucosal sugars, if combined with L-glutamine, enhance neutral NaCl absorption as well as electrogenic Na+ flow. (Aminooxy)acetate, an inhibitor of alanine aminotransferase, abolished the stimulation of QO2 and the NaCl-absorptive response to L-glutamine. We conclude that the oxidative metabolism fueled by L-glutamine is linked to a NaCl-absorptive mechanism in the intestine. We propose that the CO2 produced by glutamine metabolism yields carbonic acid, which dissociates to H+ and HCO3-, which may stimulate parallel antiports in the apical membrane.

Maleate-induced stimulation of glutamine metabolism in the intact dog kidney

1985 ◽  
Vol 248 (4) ◽  
pp. F585-F593
Author(s):  
A. Gougoux ◽  
P. Vinay ◽  
M. Duplain
Keyword(s):  
Filtration Rate ◽  
Glutamine Metabolism ◽  
Renal Metabolism ◽  
Glutamate Concentration ◽  
Metabolic Block ◽  
Dog Kidney ◽  
Total Ammonia ◽  
Lactate Utilization ◽  
Alpha Ketoglutarate Dehydrogenase ◽  
Stimulation Of

Studies were performed in anesthetized normal dogs to evaluate the effects of maleate on renal metabolism. Intravenous administration of maleate (50 mg/kg) markedly increased urinary excretion of glutamine, glutamate, alpha-ketoglutarate, alanine, lactate, pyruvate, and citrate. Despite a fourfold rise in renal cortical concentration of alpha-ketoglutarate, glutamine utilization expressed per 100 ml glomerular filtration rate almost doubled following maleate administration, whereas total ammonia production increased threefold, most of this ammonia being diverted into the renal vein. The renal production of alpha-ketoglutarate rose in a spectacular fashion and was almost equal to the renal utilization of glutamine, indicating a metabolic block at the alpha-ketoglutarate dehydrogenase step. Maleate reduced renal alanine production but did not change lactate utilization. These findings suggest that 1) in the intact dog the mitochondrial entry of glutamine is not regulated only by alpha-ketoglutarate; 2) the deamination of glutamate into alpha-ketoglutarate is accelerated by maleate, probably through an impaired mitochondrial NADH production; 3) the resulting decrement in intramitochondrial glutamate concentration deinhibits the phosphate-dependent glutaminase.

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