Effect Of Glucose Deprivation Research Articles

Phosphorus-31 nuclear magnetic resonance study of the C6 glioma cell line cultured on microcarrier beads

The energetic metabolism of perfused C6 glioma cells anchoted and cultured on polystyrene microcarrier beads has been studied by phosphorus-31 nuclear magnetic spectrocopy (NMR). The observation of in tracellular phosphorylated compounds demonstrates the metabolic long-lasting viability of the perfused cells. The effect of glucose deprivation on energetic metabolism and intracellular pH illustrates the existence of an active aerobic glycolysis. The non-invasive study of anchored C6 cells by NMR provides a direct means to investigate the metabolism of glioma cells.

Glucose deprivation results in the induction of glucose-regulated proteins and domes in MDCK monolayers in hormonally defined serum-free medium.

Madin-Darby canine kidney (MDCK) cells spontaneously form dome-like structures in vitro, a phenomenon which has been proposed to be indicative of cellular differentiation. This study indicates the existence of a correlation between the induction of domes and of glucose-regulated proteins during glucose starvation. When MDCK monolayers were glucose deprived, domes appeared very rapidly. After only 3 h of glucose deprivation domes appeared in 69% of the microscope fields. The level of expression of glucose-regulated proteins (grps) as well as domes was examined over a 6-h time interval of glucose deprivation. Both grp 76 and 97 were induced over this time interval, with grp 76 being the more readily detectable. The level of induction of grp 76 as a function of time was quantitated by means of densitometry measurements. The induction of domes was examined in parallel with the induction of grp 76. The results indicated that the induction of grp 76 and domes occurs with a similar time course. The effect of glucose deprivation on the initial rate of ouabain-sensitive Rb+ uptake was also examined. Within the first 4 h of glucose deprivation, the initial rate of ouabain-sensitive Rb+ uptake did not differ significantly in glucose-deprived and control MDCK monolayers. These observations indicate that unlike the case with other methods of dome induction (e.g., treatment with either prostaglandin E1 (PGE1) or hexamethylene bis-acetamide (HMBA] glucose deprivation does not affect the Na+K+ ATPase activity of MDCK monolayers. These observations suggest that PGE1, HMBA, and glucose deprivation affect dome formation in MDCK monolayers by means of distinct mechanisms.

O-370 - Effects of glucose-deprivation(GD), anoxia (ANX), or stop-flow ischemia (SFI) on extraneuronal O-methylating system in perfused rat hearts

O-370 - Effects of glucose-deprivation(GD), anoxia (ANX), or stop-flow ischemia (SFI) on extraneuronal O-methylating system in perfused rat hearts

The effect of glucose deprivation or 2-deoxy-D-glucose on the monodeiodination of thyroxine in human fibroblasts in culture.

The effect of glucose deprivation or 2-deoxy-D-glucose on monodeiodination of T4 to T3 and rT3 was examined in human skin fibroblasts in culture. When the cultured cells were exposed to glucose-free medium containing 1 X 10(-7) M T4 for 48 h, the cellular T4 level was similar to that of cells incubated in medium containing 1 mg/ml glucose. The intracellular T3 level significantly decreased and, in contrast, the intracellular rT3 level markedly increased compared to those levels in control cells. The intracellular T3 to T4 ratio was significantly lower, while the intracellular rT3 to T4 and rT3 to T3 ratios were significantly higher in cells exposed to glucose-free medium than in control cells. Similar results were obtained with 2-deoxy-D-glucose. Exposure of the cells to medium containing varying concentrations of 2-deoxy-D-glucose and 2 X 10(-7) M T4 for 24 h significantly reduced cellular accumulation of T4 compared with that in the control medium. The cellular rT3 to T4 and rT3 to T3 ratios were significantly greater in the cells incubated in medium with increasing concentrations of 2-deoxy-D-glucose. However, the cellular T3 to T4 ratio did not decrease in the test groups. These results, therefore, indicate that either glucose deprivation or the presence of 2-deoxy-D-glucose markedly altered the monodeiodination of T4 in cultured human fibroblasts, i.e. they caused a decrease in T3 production and, conversely, an increase in rT3 production by the cells.

Effect of glucose deprivation on the incorporation of 3H precursors into pituitiary glycoproteins and on basal LH, FSH and prolactin release

Glucose can serve as a precursor for all of the components of the oligosaccharides of glycoproteins. The incorporation of various 3H precursors into glycoproteins was examined by incubating rat anterior pituitaries in vitro for 4h in the presence and absence of glucose. Substituting succinate for glucose enhanced the incorporation of D-(2- 3H)mannose six-fold, the incorporation of D-(1, 6- 3H)-glucosamine two-fold and the incorporation of D-(6- 3H) galactose was enhanced slightly. The incorporation of other 3H precursors was unalterted or reduced by glucose deprivation. Rat anterior pituitaries incorporated minimal quantities of N-acetyl-D-(6- 3H)mannosamine, the immediate precursor of N-acetyl-D-neuraminic acid, into glycoproteins. Glucose deprivation also stimulated the 4h basal release of LH and FSH by 58% and 95%, respectively, as well as stimulated net intracellular degradation of prolactin. Thus, glucose deprivation enhances the incorporation of some, but not all, 3H precursors into glycoproteins as well as stimulates the basal release of LH and FSH.

Glucose starvation alters lipid-linked oligosaccharide biosynthesis in Chinese hamster ovary cells.

The effect of glucose deprivation on the synthesis of lipid-linked oligosaccharides by Chinese hamster ovary cells has been studied. When these cells are placed in serum-free Dulbecco's minimal essential medium devoid of glucose, there is a rapid cessation of the synthesis of the usual Glc3Man9GlcNAc2 lipid-linked oligosaccharide and the accumulation of a smaller species with the composition Man9GlcNAc2. This latter compound is the glucosylated and transferred to protein where it is subsequently processed. These findings demonstrate that Chinese hamster ovary cells utilize an alternate glycosylation pathway when deprived of glucose.

Effect of glucose deprivation on sulfatide synthesis and oligodendrocytes in cultured brain cells of newborn mice.

Summary: The present work was designed to develop a model for studying the effect of substrates on brain cell metabolism. The synthesis of sulfatide, a myelin lipid, which takes place predominantly in oligodendrocytes was measured in vitro in dissociated cell cultures of newborn mouse brains at 13 days in culture. This corresponds to an active stage of in vivo myelination. The effect of increasing durations of severe glucose deprivation (below 1 mM in the medium) was assessed on morphology, cellular protein, DNA, sulfatide synthesis, cerebroside sulfotransferase activity, and mucopolysaccharide synthesis. Glucose was rapidly consumed by the cultured cells above a concentration of 0.4 mM in the medium. At high and intermediate glucose concentrations, between 43.8 and 63.6% of the glucose consumed was accumulated as lactate on a molar ratio, indicating that the pyruvate dehydrogenase complex was rate limiting. In severe glucose deprivation, lactate consumption of the cultures exceeded accumulation. With increasing duration of severe glucose deprivation (below 1 mM), the following major changes were observed. The number of phase dark cells identified by immunofluorescence as oligoden-drocytes progressively decreased. Immunologically identified astrocytes apparently were unaffected by glucose deprivation. Sulfatide synthesis progressively dropped to 3.8% of control, and cerebroside sulfotransferase dropped to 10.3% of control with prolonged glucose deprivation. Thus, oligodendrocytes and one of their specific functions were damaged by glucose deprivation. Lactate, in spite of its being consumed by the brain cell cultures, was unable to replace glucose as a substrate for sulfatide synthesis. Uninfluenced by glucose deprivation were total cellular phosphocreatinkinase, arylsulfatase A, as well as total mucopolysaccharide synthesis by the brain cell cultures. Speculation: The present study shows that sulfatide synthesis in cultured brain cells of newborn mice at a stage corresponding to active in vivo myelination is dependent upon availability of glucose. Lactate, in spite of its being consumed by the brain cells, is unable to replace glucose with respect to sulfatide synthesis. This system of cultivated brain cells may serve as a model for studying other potential fuels for the maintenance of oligodendrocyte function.

Effect of glucose deprivation on sulfatide synthesis in dissociated brain cell cultures of newborn mice

Sulfatide synthesis (SFS) in brain cells is a marker for cell differentiation. SFS was measured by incorporation of 35S04 into sulfatide in cultured brain cells of newborn mice at 13 days in culture after exposure to various glucose concentrations for the preceding 72hrs. This age range corresponds to an in vivo developmental stage of rapid myelination. Glucose extraction from the medium during the first 24hrs was independent from the initial glucose level down to lmM. Thus the duration of severe glucose deficiency (below lmM) was related to the initial glucose supply. SFS was progressively reduced with increasing duration of severe glucose deprivation reaching 3.5% of controls after 48hrs of glucose deficiency. In the cell homogenates the sulfatide synthetizing enzyme cerebroside sulfotransferase was similarly reduced following glucose depletion keeping a residual activity of 10%. This indicates that a lack of precursors or substrates was not the only cause of SFS reduction. Replenishment of glucose stores in the medium after a starvation period of 14hrs only failed to recover SFS. Reexposure of glucose deprived cells to glucose even led to a further decrease of SFS suggesting a possible toxic effect of glucose on brain cells previously damaged by glucose depletion.

THE ROLE OF GLUCOSE IN THE INITIATION AND MAINTENANCE OF VENTRICULAR FIBRILLATION

Perfusion of isolated rabbit hearts with a glucose-free physiological solution facilitates the production of ventricular arrhythmias. On the other hand, glucose deprivation limits the duration of such arrhythmias. An hypothesis is proposed to explain the effect of glucose deprivation on the induction of fibrillation.

THE ROLE OF GLUCOSE IN THE INITIATION AND MAINTENANCE OF VENTRICULAR FIBRILLATION

Perfusion of isolated rabbit hearts with a glucose-free physiological solution facilitates the production of ventricular arrhythmias. On the other hand, glucose deprivation limits the duration of such arrhythmias. An hypothesis is proposed to explain the effect of glucose deprivation on the induction of fibrillation.

Effect of Glucose on the Growth of Influenza Virus in Deëmbryonated Eggs and Tissue Cultures

Summary When deprived of glucose, chick embryo tissues infected with influenza virus produced relatively small increments in hemagglutinin and infective virus. This effect of glucose deprivation could be reversed by the addition of glucose to deëmbryonated eggs at 48 hours and to tissue cultures as late as 5 days after infection. In tissue cultures deprived of glucose, oxygen consumption was 60 to 70% of the controls with glucose and deterioration of epithelium was observed in explants after depletion periods longer than four days. Bernkopf's observations on production from concentrated virus inocula of hemagglutinin in the absence of an increase in infective virus were confirmed in deëmbryonated eggs and in tissue cultures. Tissue cultures have been modified, without the use of complex enrichment, to produce virus yields equivalent to those obtained in the deëmbryonated egg.