THE EFFECT OF HYPERCAPNIC ACIDOSIS UPON SOME GLYCOLYTIC AND KREBS CYCLE-ASSOCIATED INTERMEDIATES IN THE RAT BRAIN |
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Authors: | Jaroslava Folbergrová V MacMillan B K Siesjö |
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Institution: | Brain Research Laboratory, E-Blocket, University Hospital, Lund, Sweden |
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Abstract: | Abstract— In order to study the influence of intracellular pH on the carbohydrate metabolism of brain tissue, the concentrations of glucose, glucose-6-phosphate, pyruvate, lactate, citrate, α-oxoglutarate, malate, glutamate, aspartate and ammonia were measured in rats exposed to 6–40% CO2, for 45 min. Hypercapnia of increasing severity gave rise to progressive increases in the concentrations of glucose, glucose-6-phosphate and ammonium ion and to progressive decreases in the concentrations of all metabolic acids measured. The results fit with aH+ inhibition of a rate-limiting step between glucose-6-phosphate and pyruvate, and by inference from the results published by others it may be assumed that this step is the phosphofructokinase reaction. Since the proportionally largest decrease occurred in a α-oxoglutarate, the results might be compatible either with an inhibition of a second rate-limiting step such as isocitrate dehydrogenase, or with a loss of α-oxoglutarate through carboxylation to citrate. |
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