Pentose phosphate pathway in cellular trophoblasts from full-term human placentas

1991 ◽  
Vol 261 (6) ◽  
pp. C1042-C1047 ◽  
Author(s):  
A. J. Moe ◽  
D. R. Farmer ◽  
D. M. Nelson ◽  
C. H. Smith
Keyword(s):  
Amino Acids ◽  
Methylene Blue ◽  
Glucose Metabolism ◽  
Electron Acceptor ◽  
Pentose Phosphate Pathway ◽  
Cultured Cells ◽  
Minor Component ◽  
Pentose Phosphate ◽  
Full Term ◽  
A Minor

Glucose metabolism was investigated in cellular trophoblasts isolated from full-term human placentas. The specific yields of 14CO2 from D-[1-14C]glucose and D-[6-14C]glucose were used to determine glucose metabolism via the pentose cycle for cells freshly isolated or cells grown in culture for 1 and 3 days. Cells were mononucleated on day 1 but fused to form multinucleated syncytiotrophoblasts by day 3. The principal product of glucose metabolism under all conditions was lactate, accounting for approximately three-fourths of recovered 14C in products. Pentose cycle activity contributed 0.57 +/- 0.01, 0.39 +/- 0.06, and 0.21 +/- 0.05% of the glucose metabolized by cells freshly isolated, cultured for 1 day, and cultured for 3 days, respectively. In the presence of the electron acceptor methylene blue, pentose cycle activity increased to 16.5 +/- 2.1, 13.8 +/- 1.5, and 18.2 +/- 1.7% for cells freshly isolated, cultured for 1 day, and cultured for 3 days, respectively. Trace amounts of 14C were recovered in other products including amino acids and glycogen. These data suggest that pentose cycle activity in cellular trophoblasts from full-term placenta, like those in full-term villous tissue, is a minor component of glucose metabolism. However, these cultured cells maintain a capacity to oxidize glucose via the pentose cycle at relatively high rates.

Pathways of glucose catabolism in Mycobacterium smegmatis

1976 ◽  
Vol 22 (9) ◽  
pp. 1374-1380 ◽  
Author(s):  
N. Jayanthi Bai ◽  
M. Ramachandra Pai ◽  
P. Suryanarayana Murthy ◽  
T. A. Venkitasubramanian
Keyword(s):  
Glucose Metabolism ◽  
Carbon Source ◽  
Pentose Phosphate Pathway ◽  
Mycobacterium Smegmatis ◽  
Pentose Phosphate ◽  
Minor Role ◽  
Key Enzymes ◽  
Glucose Catabolism ◽  
A Minor ◽  
Cells Cultured

Glucose metabolism in Mycobacterium smegmatis was investigated by the radiorespirometric method and by assaying for key enzymes of the major energy-yielding pathways. Glucose is oxidized in this organism mainly through the Embden–Meyerhof–Parnas pathway, irrespective of the carbon source used for growth. The pentose phosphate pathway plays only a minor role and its extent depends on the carbon source used for growth. Enzymes of glycolytic and oxidative pathways were detected in cells grown on glucose, glycerol, or pyruvate but enzymes of the Entner–Doudoroff pathway could be detected only in glucose-grown cells. Labeled acetate is utilized by cells cultured on glucose, glycerol, and pyruvate. In all cases more of C1 of acetate was converted to CO2 while incorporation into cellular constituents was maximum from C2 of acetate.

Clinical Studies on Glucose Metabolism via the Pentose Phosphate Pathway in Human Erythrocytes

1964 ◽  
Vol 10 (11) ◽  
pp. 1050-1053 ◽  
Author(s):  
Edwin G Olmstead ◽  
John H Lunseth
Keyword(s):  
Methylene Blue ◽  
Glucose Metabolism ◽  
Pernicious Anemia ◽  
Pentose Phosphate Pathway ◽  
Clinical Studies ◽  
Reticulocyte Count ◽  
Pentose Phosphate ◽  
Human Erythrocytes ◽  
O2 Uptake ◽  
Hemoglobin Content

Abstract Glucose metabolism via the pintos phosphate pathway was studied by measuring accelerated O2 uptake of human erythrocytes in the presence of methylene blue. Erythrocyte 02 uptake was independent of age in 67 normal patients. Erythrocyte 02 uptake was increased in pernicious anemia in relapse and in 5 of 6 jaundiced patients but was normal in pernicious anemia in remission and in 20 cases of malignancies of various types. In the latter cases there was no correlation between erythrocyte 02 uptake and hemoglobin content or reticulocyte count.

scholarly journals Insulin stimulates glucose metabolism via the pentose phosphate pathway in Drosophila Kc cells

FEBS Letters ◽  
2003 ◽  
Vol 555 (2) ◽  
pp. 307-310 ◽  
Author(s):  
Rolando B. Ceddia ◽  
George J. Bikopoulos ◽  
Arthur J. Hilliker ◽  
Gary Sweeney
Keyword(s):  
Glucose Metabolism ◽  
Pentose Phosphate Pathway ◽  
Pentose Phosphate

scholarly journals Role of Intracellular Carbon Metabolism Pathways in Shigella flexneri Virulence

2014 ◽  
Vol 82 (7) ◽  
pp. 2746-2755 ◽  
Author(s):  
E. A. Waligora ◽  
C. R. Fisher ◽  
N. J. Hanovice ◽  
A. Rodou ◽  
E. E. Wyckoff ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Pentose Phosphate Pathway ◽  
Carbon Metabolism ◽  
Cultured Cells ◽  
Shigella Flexneri ◽  
Plaque Assay ◽  
Pentose Phosphate ◽  
Host Cells ◽  
Content Type ◽  
Pathway Gene

ABSTRACTShigella flexneri, which replicates in the cytoplasm of intestinal epithelial cells, can use the Embden-Meyerhof-Parnas, Entner-Doudoroff, or pentose phosphate pathway for glycolytic carbon metabolism. To determine which of these pathways is used by intracellularS. flexneri, mutants were constructed and tested in a plaque assay for the ability to invade, replicate intracellularly, and spread to adjacent epithelial cells. Mutants blocked in the Embden-Meyerhof-Parnas pathway (pfkABandpykAFmutants) invaded the cells but formed very small plaques. Loss of the Entner-Doudoroff pathway geneedaresulted in small plaques, but the doubleeda eddmutant formed normal-size plaques. This suggested that the plaque defect of theedamutant was due to buildup of the toxic intermediate 2-keto-3-deoxy-6-phosphogluconic acid rather than a specific requirement for this pathway. Loss of the pentose phosphate pathway had no effect on plaque formation, indicating that it is not critical for intracellularS. flexneri. Supplementation of the epithelial cell culture medium with pyruvate allowed the glycolysis mutants to form larger plaques than those observed with unsupplemented medium, consistent with data from phenotypic microarrays (Biolog) indicating that pyruvate metabolism was not disrupted in these mutants. Interestingly, the wild-typeS. flexnerialso formed larger plaques in the presence of supplemental pyruvate or glucose, with pyruvate yielding the largest plaques. Analysis of the metabolites in the cultured cells showed increased intracellular levels of the added compound. Pyruvate increased the growth rate ofS. flexneriin vitro, suggesting that it may be a preferred carbon source inside host cells.

scholarly journals The Pentose Phosphate Pathway and Pyruvate Carboxylation after Neonatal Hypoxic-Ischemic Brain Injury

2014 ◽  
Vol 34 (4) ◽  
pp. 724-734 ◽  
Author(s):  
Eva MF Brekke ◽  
Tora S Morken ◽  
Marius Widerøe ◽  
Asta K Håberg ◽  
Ann-Mari Brubakk ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Glucose Metabolism ◽  
Pentose Phosphate Pathway ◽  
De Novo ◽  
Pentose Phosphate ◽  
Adult Brain ◽  
Resonance Spectroscopy ◽  
Neonatal Brain ◽  
Artery Ligation ◽  
Pyruvate Carboxylation

The neonatal brain is vulnerable to oxidative stress, and the pentose phosphate pathway (PPP) may be of particular importance to limit the injury. Furthermore, in the neonatal brain, neurons depend on de novo synthesis of neurotransmitters via pyruvate carboxylase (PC) in astrocytes to increase neurotransmitter pools. In the adult brain, PPP activity increases in response to various injuries while pyruvate carboxylation is reduced after ischemia. However, little is known about the response of these pathways after neonatal hypoxia-ischemia (HI). To this end, 7-day-old rats were subjected to unilateral carotid artery ligation followed by hypoxia. Animals were injected with [1,2-13C]glucose during the recovery phase and extracts of cerebral hemispheres ipsi- and contralateral to the operation were analyzed using 1H- and 13C-NMR (nuclear magnetic resonance) spectroscopy and high-performance liquid chromatography (HPLC). After HI, glucose levels were increased and there was evidence of mitochondrial hypometabolism in both hemispheres. Moreover, metabolism via PPP was reduced bilaterally. Ipsilateral glucose metabolism via PC was reduced, but PC activity was relatively preserved compared with glucose metabolism via pyruvate dehydrogenase. The observed reduction in PPP activity after HI may contribute to the increased susceptibility of the neonatal brain to oxidative stress.

Metabolic activities of sheep erythrocytes. I. Glycolytic activities

1962 ◽  
Vol 13 (1) ◽  
pp. 31 ◽  
Author(s):  
RA Leng ◽  
EF Annison
Keyword(s):  
Carbon Dioxide ◽  
Methylene Blue ◽  
Lactic Acid ◽  
Oxygen Uptake ◽  
Pentose Phosphate Pathway ◽  
Glucose Oxidation ◽  
Lactic Acid Production ◽  
Pentose Phosphate ◽  
Sheep Erythrocytes ◽  
Metabolic Activities

Sheep erythrocytes, which in most animals are impermeable to glucose, show low glycolytic activities relative to human cells. When 14C-labelled glucose was incubated with erythrocyte suspensions the oxygen uptake was 10.9 ± 1.8 µl/hr/ml of cells (5 replications), and glucose oxidation (measured by recovery of [14C]carbon dioxide) was 0.03 ± 0.007 µmole/hr/ml (5). Addition of methylene blue (0.4 µmole/ ml) increased oxygen uptake to 56 ± 3.5 µl/hr/ml (5) and glucose oxidation to 0.36 ± 0.02 µmole/hr/ml. Lactic acid production was increased from 1 .5 ± 0.06 µmole/hr/ml (7) to 1.7 ± 0.11 µmole/hr/ml (7) in the presence of methylene blue. Comparison of the yields of [14C]carbon dioxide from [1-14C]glucose and uniformly labelled [14C]glucose indicated that when stimulated by methylene blue 80–100% of glycolysis proceeded by the pentose phosphate pathway, but in the unstimulated system the alternative aerobic pathway accounted for only about 15% of total glycolysis.

scholarly journals Wnt5a Increases the Glycolytic Rate and the Activity of the Pentose Phosphate Pathway in Cortical Neurons

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Pedro Cisternas ◽  
Paulina Salazar ◽  
Carmen Silva-Álvarez ◽  
L. Felipe Barros ◽  
Nibaldo C. Inestrosa
Keyword(s):  
Glucose Metabolism ◽  
Wnt Signaling ◽  
Pentose Phosphate Pathway ◽  
Neurodegenerative Disorders ◽  
Metabolic Flux ◽  
High Energy ◽  
Pentose Phosphate ◽  
The Brain ◽  
Glycolytic Rate

In the last few years, several reports have proposed that Wnt signaling is a general metabolic regulator, suggesting a role for this pathway in the control of metabolic flux. Wnt signaling is critical for several neuronal functions, but little is known about the correlation between this pathway and energy metabolism. The brain has a high demand for glucose, which is mainly used for energy production. Neurons use energy for highly specific processes that require a high energy level, such as maintaining the electrical potential and synthesizing neurotransmitters. Moreover, an important metabolic impairment has been described in all neurodegenerative disorders. Despite the key role of glucose metabolism in the brain, little is known about the cellular pathways involved in regulating this process. We report here that Wnt5a induces an increase in glucose uptake and glycolytic rate and an increase in the activity of the pentose phosphate pathway; the effects of Wnt5a require the intracellular generation of nitric oxide. Our data suggest that Wnt signaling stimulates neuronal glucose metabolism, an effect that could be important for the reported neuroprotective role of Wnt signaling in neurodegenerative disorders.

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