TY - JOUR
T1 - Up-regulation of glucose metabolism in Kupffer cells following infusion of tumour necrosis factor
AU - Spolarics, Z.
AU - Bagby, G. J.
AU - Lang, C. H.
AU - Spitzer, J. J.
PY - 1991
Y1 - 1991
N2 - Alterations of glucose metabolism and the oxidation of glutamine and palmitate were studied, by using specifically labelled substrates, in freshly isolated Kupffer cells and hepatic endothelial cells after infusion in vivo of human recombinant tumour necrosis factor-α (TNF; 7.5 x 105 IU/30 min per kg body wt., intravenously). Cells were incubated in a medium containing 5 mM-glucose, 0.4 mM-palmitate, 1 mM-lactate and 0.5 mM-glutamine. Administration of TNF in vivo increased glucose use in Kupffer cells by 70%. Glucose oxidation in the tricarboxylic acid cycle and flux in the Embden-Meyerhof (EM) pathway were elevated by 40 and 80% respectively. Treatment in vitro with 1 μM-phorbol 12-myristate 13-acetate (PMA) resulted in a similar percentage increase in glucose use by Kupffer cells prepared from either saline- or TNF-treated rats. However, PMA increased the activity of the hexose monophosphate shunt (HMS) by 3- and 10-fold in cells isolated from saline- or TNF-infused animals respectively. A phagocyte stimulus in vitro, opsonized zymosan, increased glucose use by 30% and doubled the flux through the HMS in Kupffer cells from saline-infused animals. The activity of the HMS in response to zymosan was increased by 400% after TNF treatment. In endothelial cells, basal glucose utilization was not altered by TNF treatment. PMA increased HMS activity in endothelial cells to a similar degree after saline or TNF infusion. Zymosan, however, increased HMS activity only in endothelial cells from TNF-treated rats. Oxidation of palmitate or glutamine was not affected by TNF treatment either under basal conditions or after challenge in vitro. Our data indicate that, after phagocytosis in vitro or protein kinase C activation, glucose use and flux through the HMS increase in Kupffer cells. This is accompanied by increased glycolytic flux, with no changes in glucose oxidation in the tricarboxylic acid cycle. After TNF exposure, followed by a secondary stimulus, the enhanced glucose use by Kupffer cells is primarily channelled through the HMS pathway. These data suggest that the increased glucose use in vivo by Kupffer cells found after immune-stimulated conditions may subserve primarily the increased need for NADPH and HMS intermediates.
AB - Alterations of glucose metabolism and the oxidation of glutamine and palmitate were studied, by using specifically labelled substrates, in freshly isolated Kupffer cells and hepatic endothelial cells after infusion in vivo of human recombinant tumour necrosis factor-α (TNF; 7.5 x 105 IU/30 min per kg body wt., intravenously). Cells were incubated in a medium containing 5 mM-glucose, 0.4 mM-palmitate, 1 mM-lactate and 0.5 mM-glutamine. Administration of TNF in vivo increased glucose use in Kupffer cells by 70%. Glucose oxidation in the tricarboxylic acid cycle and flux in the Embden-Meyerhof (EM) pathway were elevated by 40 and 80% respectively. Treatment in vitro with 1 μM-phorbol 12-myristate 13-acetate (PMA) resulted in a similar percentage increase in glucose use by Kupffer cells prepared from either saline- or TNF-treated rats. However, PMA increased the activity of the hexose monophosphate shunt (HMS) by 3- and 10-fold in cells isolated from saline- or TNF-infused animals respectively. A phagocyte stimulus in vitro, opsonized zymosan, increased glucose use by 30% and doubled the flux through the HMS in Kupffer cells from saline-infused animals. The activity of the HMS in response to zymosan was increased by 400% after TNF treatment. In endothelial cells, basal glucose utilization was not altered by TNF treatment. PMA increased HMS activity in endothelial cells to a similar degree after saline or TNF infusion. Zymosan, however, increased HMS activity only in endothelial cells from TNF-treated rats. Oxidation of palmitate or glutamine was not affected by TNF treatment either under basal conditions or after challenge in vitro. Our data indicate that, after phagocytosis in vitro or protein kinase C activation, glucose use and flux through the HMS increase in Kupffer cells. This is accompanied by increased glycolytic flux, with no changes in glucose oxidation in the tricarboxylic acid cycle. After TNF exposure, followed by a secondary stimulus, the enhanced glucose use by Kupffer cells is primarily channelled through the HMS pathway. These data suggest that the increased glucose use in vivo by Kupffer cells found after immune-stimulated conditions may subserve primarily the increased need for NADPH and HMS intermediates.
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U2 - 10.1042/bj2780515
DO - 10.1042/bj2780515
M3 - Article
C2 - 1898344
AN - SCOPUS:0025861218
VL - 278
SP - 515
EP - 519
JO - Biochemical Journal
JF - Biochemical Journal
SN - 0264-6021
IS - 2
ER -