TY - JOUR
T1 - Jejunal epithelial glucose metabolism
T2 - Effects of Na+ replacement
AU - Mallet, R. T.
AU - Jackson, M. J.
AU - Kelleher, J. K.
PY - 1986
Y1 - 1986
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=0023026292&partnerID=8YFLogxK
U2 - 10.1152/ajpcell.1986.251.5.c803
DO - 10.1152/ajpcell.1986.251.5.c803
M3 - Article
C2 - 3777159
AN - SCOPUS:0023026292
SN - 0363-6143
VL - 251
SP - C803-C809
JO - American Journal of Physiology - Cell Physiology
JF - American Journal of Physiology - Cell Physiology
IS - 5 (20/5)
ER -