Glucose and glutamine metabolism in C6 glioma cells studied by carbon 13 NMR

Influence of Serum and Hypoxia on Incorporation of [14C]‐d‐Glucose or [14C]‐l‐Glutamine into Lipids and Lactate in Murine Glioblastoma Cells

“…However, we detected only minimal amounts of lactate derived from glutamine. Our findings are therefore consistent with the previous reports showing minimal lactate produced from glutamine [3,24]. Inherently, this could be a cell line specific phenomenon similar to that of HeLa cells, where it is estimated that only 13 % of glutamine was converted to lactate [40].…”

Influence of Serum and Hypoxia on Incorporation of [14C]‐d‐Glucose or [14C]‐l‐Glutamine into Lipids and Lactate in Murine Glioblastoma Cells

“…However, we detected only minimal amounts of lactate derived from glutamine. Our findings are therefore consistent with the previous reports showing minimal lactate produced from glutamine [3,24]. Inherently, this could be a cell line specific phenomenon similar to that of HeLa cells, where it is estimated that only 13 % of glutamine was converted to lactate [40].…”

Contribution of Extracellular Glutamine as An Anaplerotic Substrate to Neuronal Metabolism: A Re-Evaluation by Multinuclear NMR Spectroscopy in Primary Cultured Neurons

“…Thus, because unlabelled glutamine would lead to unlabelled glutamate, the increase of glutamate was mainly attributed to the metabolism of 13 C-labelled glucose. The observation of increased conversion of glucose to glutamate in the presence of glutamine is consistent with the ''isotopic-exchange process'' between unlabelled glutamine and [1-13 C]glucose previously observed in C6 glioma cells (20) and primary astrocytes (21). However, since glutamine represents both a carbon-and a nitrogen source, it is reasonable to assume that ammonia, which is set free by glutaminase, stimulates subsequently neuronal amino acid synthesis from glucose in order to detoxify ammonia.…”

[1‐13C]Glucose Metabolism in the Tumoral and Nontumoral Cerebral Tissue of a Glioma‐Bearing Rat

“…This indicates a low (if any) recycling of glutamine carbons in the TCA cycle via pyruvate and acetyl‐CoA, i.e., that glutamine is used rather for the cell anabolic needs than as an oxidative substrate. This behavior, as well as the lack of glutamine synthetase activity, is similar to that evidenced for cultured C6 cells (Portais et al, 1996).…”

Influence of Serum and Hypoxia on Incorporation of [14C]‐d‐Glucose or [14C]‐l‐Glutamine into Lipids and Lactate in Murine Glioblastoma Cells

“…However, we detected only minimal amounts of lactate derived from glutamine. Our findings are therefore consistent with the previous reports showing minimal lactate produced from glutamine [3,24]. Inherently, this could be a cell line specific phenomenon similar to that of HeLa cells, where it is estimated that only 13 % of glutamine was converted to lactate [40].…”

Contribution of Extracellular Glutamine as An Anaplerotic Substrate to Neuronal Metabolism: A Re-Evaluation by Multinuclear NMR Spectroscopy in Primary Cultured Neurons

“…Thus, because unlabelled glutamine would lead to unlabelled glutamate, the increase of glutamate was mainly attributed to the metabolism of 13 C-labelled glucose. The observation of increased conversion of glucose to glutamate in the presence of glutamine is consistent with the ''isotopic-exchange process'' between unlabelled glutamine and [1-13 C]glucose previously observed in C6 glioma cells (20) and primary astrocytes (21). However, since glutamine represents both a carbon-and a nitrogen source, it is reasonable to assume that ammonia, which is set free by glutaminase, stimulates subsequently neuronal amino acid synthesis from glucose in order to detoxify ammonia.…”

[1‐13C]Glucose Metabolism in the Tumoral and Nontumoral Cerebral Tissue of a Glioma‐Bearing Rat

“…This indicates a low (if any) recycling of glutamine carbons in the TCA cycle via pyruvate and acetyl‐CoA, i.e., that glutamine is used rather for the cell anabolic needs than as an oxidative substrate. This behavior, as well as the lack of glutamine synthetase activity, is similar to that evidenced for cultured C6 cells (Portais et al, 1996).…”

Influence of Serum and Hypoxia on Incorporation of [14C]‐d‐Glucose or [14C]‐l‐Glutamine into Lipids and Lactate in Murine Glioblastoma Cells

“…However, we detected only minimal amounts of lactate derived from glutamine. Our findings are therefore consistent with the previous reports showing minimal lactate produced from glutamine [3,24]. Inherently, this could be a cell line specific phenomenon similar to that of HeLa cells, where it is estimated that only 13 % of glutamine was converted to lactate [40].…”

Contribution of Extracellular Glutamine as An Anaplerotic Substrate to Neuronal Metabolism: A Re-Evaluation by Multinuclear NMR Spectroscopy in Primary Cultured Neurons

“…Thus, because unlabelled glutamine would lead to unlabelled glutamate, the increase of glutamate was mainly attributed to the metabolism of 13 C-labelled glucose. The observation of increased conversion of glucose to glutamate in the presence of glutamine is consistent with the ''isotopic-exchange process'' between unlabelled glutamine and [1-13 C]glucose previously observed in C6 glioma cells (20) and primary astrocytes (21). However, since glutamine represents both a carbon-and a nitrogen source, it is reasonable to assume that ammonia, which is set free by glutaminase, stimulates subsequently neuronal amino acid synthesis from glucose in order to detoxify ammonia.…”

[1‐13C]Glucose Metabolism in the Tumoral and Nontumoral Cerebral Tissue of a Glioma‐Bearing Rat

“…This indicates a low (if any) recycling of glutamine carbons in the TCA cycle via pyruvate and acetyl‐CoA, i.e., that glutamine is used rather for the cell anabolic needs than as an oxidative substrate. This behavior, as well as the lack of glutamine synthetase activity, is similar to that evidenced for cultured C6 cells (Portais et al, 1996).…”