1978 |
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Hume, D. A.; Radik, J. L.; Ferber, E.; Weidemann, M. J. Aerobic glycolysis and lymphocyte transformation (Journal Article) In: Biochemical Journal, vol. 174, no. 3, pp. 703–709, 1978, ISSN: 02646021. (Abstract | Links | BibTeX | Altmetric) @article{hume_aerobic_1978, The role of enhanced aerobic glycolysis in the transformation of rat thymocytes by concanavalin A has been investigated. Concanavalin A addition doubled [U-14C]glucose uptake by rat thymocytes over 3h and caused an equivalent increased incorporation into protein, lipids and RNA. A disproportionately large percentage of the extra glucose taken up was converted into lactate, but concanavalin A also caused a specific increase in pyruvate oxidation, leading to an increase in the percentage contribution of glucose to the respiratory fuel. Acetoacetate metabolism, which was not affected by concanavalin A, strongly suppressed pyruvate oxidation in the presence of [U-14C]glucose, but did not prevent the concanavalin A-induced stimulation of this process. Glucose uptake was not affected by acetoacetate in the presence or absence of concanavalin A, but in each case acetoacetate increased the percentage of glucose uptake accounted for by lactate production. [3H]Thymidine incorporation into DNA in concanavalin A-treated thymocyte cultures was sensitive to the glucose concentration in the medium in a biphasic manner. Very low concentrations of glucose (25 μM) stimulated DNA synthesis half-maximally, but maximum [3H]thymidine incorporation was observed only when the glucose concentration was raised to 1mM. Lactate addition did not alter the sensitivity of [3H]-thymidine uptake to glucose, but inosine blocked the effect of added glucose and strongly inhibited DNA synthesis. It is suggested that the major function of enhanced aerobic glycolysis in transforming lymphocytes is to maintain higher steady-state amounts of glycolytic intermediates to act as precursors for macromolecule synthesis. | |
1977 |
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Yasmeen, D.; Laird, A. J.; Hume, D. A.; Weidemann, M. J. In: BBA - General Subjects, vol. 500, no. 1, pp. 89–102, 1977, ISSN: 03044165. (Abstract | Links | BibTeX | Altmetric) @article{yasmeen_activation_1977, 1. 1. A method is described for the determination of the rate of 3-O-methyl-D-[U-14C]glucose transport into rat thymuse lymphocytes. Some kinetic properties of this facilitated diffusion transport process have been determined, both before and after stimulation with concanavalin A, and the effects of Ca2+, puromycin and cycloheximide have been investigated. 2. 2. The initial rate of 3-O-methyl-D-glucose transport into rat thymus lymphocytes is significantly stimulated within 5 min of concanavalin A addition and is approximately doubled after 30 min. 3. 3. Maximun stimulation of sugar transport by concanavalin A requires at least 30 μM free Ca2+ in the extracellular medium, and is sigmoidally dependent on free Ca2+ up to this concentration; in contrast, the unstimulated transport process appears to be Ca2+-independent. 4. 4. In both the presence and absence of concanavalin A, 3-O-methyl-D-glucose transport is a saturable process with a Km of approx. 4.5 mM; the stimulation by concanavalin A can be attributed solely to a two-fold increase in the value of V, as the Km value remains essentially unaltered. 5. 5. Concanavalin A alters the temperature-dependence of 3-O-methyl-D-glucose transport so that the activation energy at 37°C is substantially increased. 6. 6. The enhancement of sugar transport by concanavalin A is independent of de novo protein synthesis, as it is not prevented by cycloheximide, which blocks the incorporation of [14C]leucine into trichloroacetic acid-precipitation protein. 7. 7. On the other hand, the stimulation of 3-0-methyl-D-glucose transport by concanavalin A, as well as the enhanced utilization of D-glucose, is suppressed by puromycin, which also blocks [14C]leucine incorporation into protein. This suppression appears to be due to a hitherto unreported inhibitory effect of puromycin on glucose transport. © 1977. | |
1976 |
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hume, D. A.; weidemann, M. J. Hormonal regulation of gluconeogenesis in isolated rat hepatocytes: An undergraduate experiment (Journal Article) In: Biochemical Education, vol. 4, no. 1, pp. 13–14, 1976, ISSN: 03074412. @article{hume_hormonal_1976, |
1978 |
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Aerobic glycolysis and lymphocyte transformation (Journal Article) In: Biochemical Journal, vol. 174, no. 3, pp. 703–709, 1978, ISSN: 02646021. | |
1977 |
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In: BBA - General Subjects, vol. 500, no. 1, pp. 89–102, 1977, ISSN: 03044165. | |
1976 |
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Hormonal regulation of gluconeogenesis in isolated rat hepatocytes: An undergraduate experiment (Journal Article) In: Biochemical Education, vol. 4, no. 1, pp. 13–14, 1976, ISSN: 03074412. |