Jejunal epithelial glucose metabolism: Effects of Na+ replacement

Robert T. Mallet, M. J. Jackson, J. K. Kelleher

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The objective of this study was to characterize the effects of replacement of extracellular Na+ with a nontransportable cation, N-methyl-D-glucamine (NMDG+) on jejunal epithelial glucose metabolism. Jejunal epithelium isolated from male Sprague-Dawley rats was incubated in media containing 5 mM glucose, 0.5 mM glutamine, 0.5 mM β-hydroxybutyrate, and 0.3 mM acetoacetate as the principal carbon sources. O2 consumption and total glucose utilization were reduced 30 and 50%, respectively, when Na+ was replaced with NMDG+. In both media, ~75% of utilized glucose carbon was converted to lactate. The rate of glucose metabolism via the hexose monophosphate shunt, as evaluated using specific 14CO2 yields from [1-14C]glucose and [6-14C]glucose, was not appreciably altered by Na+ replacement. Tricarboxylic acid (TCA) cycle flux was evaluated using 14CO2 production from [14C]glucose and [14C] pyruvate radioisotopes. Approximately 50% of TCA cycle flux was shunted into products other than CO2 in both media. The majority of the actyl-CoA oxidized in the TCA cycle was derived from cytosolic pyruvate. It is concluded that removal of Na+ from the bathing medium substantially reduced glucose utilization via the Embden-Meyerhof pathway and TCA cycle in the jejunal epithelium.

Original languageEnglish
JournalAmerican Journal of Physiology - Cell Physiology
Volume251
Issue number5
StatePublished - 1 Dec 1986

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Metabolism
Glucose
Citric Acid Cycle
Pyruvic Acid
Carbon
Epithelium
Fluxes
Hydroxybutyrates
Pentose Phosphate Pathway
Hexoses
Glycolysis
Coenzyme A
Glutamine
Radioisotopes
Sprague Dawley Rats
Cations
Rats
Lactic Acid

Cite this

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title = "Jejunal epithelial glucose metabolism: Effects of Na+ replacement",
abstract = "The objective of this study was to characterize the effects of replacement of extracellular Na+ with a nontransportable cation, N-methyl-D-glucamine (NMDG+) on jejunal epithelial glucose metabolism. Jejunal epithelium isolated from male Sprague-Dawley rats was incubated in media containing 5 mM glucose, 0.5 mM glutamine, 0.5 mM β-hydroxybutyrate, and 0.3 mM acetoacetate as the principal carbon sources. O2 consumption and total glucose utilization were reduced 30 and 50{\%}, respectively, when Na+ was replaced with NMDG+. In both media, ~75{\%} of utilized glucose carbon was converted to lactate. The rate of glucose metabolism via the hexose monophosphate shunt, as evaluated using specific 14CO2 yields from [1-14C]glucose and [6-14C]glucose, was not appreciably altered by Na+ replacement. Tricarboxylic acid (TCA) cycle flux was evaluated using 14CO2 production from [14C]glucose and [14C] pyruvate radioisotopes. Approximately 50{\%} of TCA cycle flux was shunted into products other than CO2 in both media. The majority of the actyl-CoA oxidized in the TCA cycle was derived from cytosolic pyruvate. It is concluded that removal of Na+ from the bathing medium substantially reduced glucose utilization via the Embden-Meyerhof pathway and TCA cycle in the jejunal epithelium.",
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Jejunal epithelial glucose metabolism : Effects of Na+ replacement. / Mallet, Robert T.; Jackson, M. J.; Kelleher, J. K.

In: American Journal of Physiology - Cell Physiology, Vol. 251, No. 5, 01.12.1986.

Research output: Contribution to journalArticle

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