Lactic acidosis and renal phosphoenolpyruvate carboxykinase activity during exercise

Sanchez-Urrutia, L.; García–Ruiz, Josefa P.; Sánchez-Medina, F; Mayor, Federico

doi:10.1016/0006-2944(75)90054-x

Cited by 9 publications

(4 citation statements)

References 38 publications

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“…2b) Metabolic acidosis produces a strong in duction of gluconeogenesis in rat kidney cor tex that in some circumstances may be related to ammonia production [3, 4, 14]. Exercise induces both acidosis and renal gluconeogene sis [14]. After 2 h exercise under our experi mental conditions blood pH dropped from 7.37 ± 0.01 to 7.06 ± 0.03 and HCO3 con centration from 22.1 ± 0.5 to 14.5 ± 0.6 max mmol/1.…”

Section: Materials and Methods Results And Discussionmentioning

confidence: 99%

Regulation of Rat-Renal Cortex Phosphofructokinase Activity by pH

Sola

Salto²,

Oliver³

et al. 1993

Enzyme Protein

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The activity of phosphofructokinase purified from rat kidney cortex has been assayed at two different pH values. At pH 7 the enzyme showed cooperativity for the binding of fructose 6-phosphate (Fru-6-P) and a strong allosteric inhibition by ATP. When the assays were done at pH 8 hyperbolic kinetics were observed for both substrates, a smaller inhibition by ATP was observed and the V(max) for ATP and for Fru-6-P was higher than at pH 7. A sequential reaction mechanism was inferred. Results are discussed in terms of the importance of a reduced hexose-phosphate cycling rate during metabolic acidosis induced by exercise.

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Section: Materials and Methods Results And Discussionmentioning

confidence: 99%

Regulation of Rat-Renal Cortex Phosphofructokinase Activity by pH

Sola

Salto²,

Oliver³

et al. 1993

Enzyme Protein

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“…After they were fasted overnight, Sprague Dawley rats (150-250 g) were exercised by being forced to swim in a waterbath for 15 min (Sanchez-Urrutia et al 1975). Controls were not exercised.…”

Section: Methodsmentioning

confidence: 99%

Renal Ammoniagenesis in Rats Made Acutely Acidotic by Swimming

Hortelano¹,

Lupiáñez²,

Barnswell³

et al. 1984

Horm Metab Res

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Rats develop metabolic acidosis acutely after exercise by swimming. Renal cortical slices from exercised rats show an increase in both ammoniagenesis and gluconeogenesis from glutamine. In addition, plasma from the exercised rats also stimulates ammoniagenesis in renal cortical slices from normal rats. In exercised rats renal phosphate dependent glutaminase shows a 200% activation when the enzyme activity is measured at subsaturating concentration of glutamine (1 mM) while only an increase of 12% in Vmax is observed. When kidney slices from normal rats are incubated in plasma from exercised rats an activation of phosphate dependent glutaminase is obtained with a 1.0 mM (100%) but not with 20 mM glutamine as substrate. This activation of phosphate dependent glutaminase at subsaturating levels of substrate may indicate a conformational change in PDG effected by a factor present in the plasma of exercised acidotic rats.

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“…These effects are probably mediated by the metabolic acidosis which takes place during exercise as result of muscular overproduction of lactate [3].…”

Section: Introductionmentioning

confidence: 99%

“…These effects are probably mediated by the metabolic acidosis which takes place during exercise as result of muscular overproduction of lactate [3].The increase of renal gluconeogenesis in experimental metabolic acidosis seems to be related to the enhancement of the reaction catalyzed by phosphoenolpyruvate carboxykinase, as indicated by the concentrations of intermediate metabolites of this process [4,5]. Consequently, we have measured the content of gluconeogenic intermediates in kidney after 2 h of swimming in order to obtain further evidence on the relation between the effect of exercise on gluconeogenesis and metabolic acidosis.…”

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confidence: 99%

Effect of short‐term exercise on the content of gluconeogenic metabolites in rat liver and kidney

et al. 1979

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We have reported that muscular exercise (swimming in water at 22'C for 2 h)enhances the activity of phosphoenolpyruvate carboxykinase and the gluconeogenic capacity of rat kidney cortex [I ,2]. These effects are probably mediated by the metabolic acidosis which takes place during exercise as result of muscular overproduction of lactate [3].The increase of renal gluconeogenesis in experimental metabolic acidosis seems to be related to the enhancement of the reaction catalyzed by phosphoenolpyruvate carboxykinase, as indicated by the concentrations of intermediate metabolites of this process [4,5]. Consequently, we have measured the content of gluconeogenic intermediates in kidney after 2 h of swimming in order to obtain further evidence on the relation between the effect of exercise on gluconeogenesis and metabolic acidosis. Materials aud methodsFemale Wistar rats (150-200 g) were used. The animals were forced to swim in a water bath (22°C) for 2 h. At the end of exercise, they were sacrificed by cervical dislocation. A-portion of liver or one of the kidneys was rapidly excised and clamped between metal tongs precooled in liquid nitrogen [6]. The time elapsing between dislocation of the neck and freezing the organ was 8-10 s. The frozen tissue was pulverized in a mortar, extracted with perchloric acid solution and neutralized with KOII, as in 171.Lactate was determined as in [8] ; aspartate as in Results and diicussionIn the liver from exercised rats the content of lactate was decreased whereas the concentrations of malate, aspartate ,2-phosphoglycerate , fructose 6-phosphate and glucose 6-phosphate were increased (table 1). Assuming that the content of malate and aspartate reflect that of oxalacetate (which is unstable and present in small concentrations in tissues), the rise in malate and aspartate in connection with the absence of a significant e~~cement for phosphoenolpyruvate indicate a low activity of phosphoenolpyruvate carboxykinase . Therefore, the decrease in lactate content is not likely due to gluconeogenesis but to oxidative consumption in the tricarboxylic acid cycle. On the other hand, the rise in fructose 6-phosphate and glucose 6-phosphate can be explained by the operation of glycogenolysis. It is well established that glycogen degradation takes place during exercise [14].The effect of exercise on the renal content of ghrconeogenic intermediates is shown in table 2. Like in liver, lactate was decreased and there was a rise in the content of fructose 6-phosphate and glucose 6-phosphate. On the contrary, mrtlate and 2-phosphoglycerate did not charge, asparate and fructose bisElsevier/North-IioIkmd Biomedical Press

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Lactic acidosis and renal phosphoenolpyruvate carboxykinase activity during exercise

Cited by 9 publications

References 38 publications

Regulation of Rat-Renal Cortex Phosphofructokinase Activity by pH

Regulation of Rat-Renal Cortex Phosphofructokinase Activity by pH

Renal Ammoniagenesis in Rats Made Acutely Acidotic by Swimming

Effect of short‐term exercise on the content of gluconeogenic metabolites in rat liver and kidney

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