Stimulation of the pentose phosphate pathway and glutathione levels by dehydroascorbate, the oxidized form of vitamin C

SummaryA study was made of the changes in the rates of oxidation of the C(1), C(2) and C(6) atoms of glucose and in the pathways of glucose catabolism in sheep udder tissue in vitro which occurred when acetate and pyruvate were added.Whereas in rat mammary tissue the rate of oxidation of the C(1) atom of glucose was very much greater than that of the C(6) atom, the ratio of the rates of oxidation of these 2 atoms in sheep tissue was less than 2 when glucose was the only substrate.The addition of acetate resulted in an unequal stimulation of the oxidation of these 2 atoms, with the result that the ratio of their rates of oxidation was about doubled. The rate of oxidation of the C(2) atom was also increased.Acetate also increased the participation of the pentose phosphate pathway in glucose catabolism as measured by the incorporation of the C(1) and C(6) atoms of glucose into fatty acids, lactic acid and glycerol.Pyruvate produced little effect on the rate of oxidation of the C(1) atom but somewhat depressed that of the C(6) atom of glucose. At the same time, it caused a large increase in the participation of the pentose phosphate pathway.These results are discussed with reference to re-cycling of glucose carbon in the pentose phosphate pathway and to the relationship between that pathway and fatty acid synthesis. It is noted that the incorporation of glucose carbon into the 3 intermediates used gave values for the participation of that pathway which were in better agreement than was obtained in rat tissue. It is concluded that triose phosphates are more nearly in equilibrium in sheep than in rat mammary tissue.

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The effect of serum from obese and normal weight men on glucose metabolism in leucocytes

Acta Endocrinologica ◽

10.1530/acta.0.0950134 ◽

1980 ◽

Vol 95 (1) ◽

pp. 134-138 ◽

Cited By ~ 1

Author(s):

Ole Myking ◽

Berit Kjøsen ◽

Hans H. Bassøe

Keyword(s):

Glucose Metabolism ◽

Pentose Phosphate Pathway ◽

Lactate Production ◽

Normal Weight ◽

Pentose Phosphate ◽

Obese Group ◽

Stimulation Of

Abstract. The influence of pooled serum from either obese or normal weight males on glucose metabolism in human leucocytes has been studied. Leucocytes from normal weight males were incubated with 10–90% pooled serum and either [U-14C], or [1-14C]glucose. Compared to serum from the normal weight males, serum from the obese group had a more stimulating effect on the 14CO2 and [14C]lactate production from [U-14C]glucose and on the 14CO2 production from [1-14C]glucose. The two serum pools had the same stimulating effect on the Embden-Meyerhof pathway as indicated by the formation of [14C]lactate from [1-14C]glucose. Calculations revealed that the activity in the pentose phosphate pathway was stimulated more by serum from obese, than from normal weight males. It is a possibility that increased stimulation of the pentose phosphate pathway may contribute to the development of overweight.

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Improving salinity resilience in Swertia chirayita clonal line with Lactobacillus plantarum

Canadian Journal of Plant Science ◽

10.1139/cjps-2015-0178 ◽

2016 ◽

Vol 96 (1) ◽

pp. 117-127 ◽

Cited By ~ 3

Author(s):

Susanna Phoboo ◽

Dipayan Sarkar ◽

Prasanta C. Bhowmik ◽

Pramod Kumar Jha ◽

Kalidas Shetty

Keyword(s):

Dehydrogenase Activity ◽

Lactobacillus Plantarum ◽

Salinity Stress ◽

Pentose Phosphate Pathway ◽

Krebs Cycle ◽

Defense Responses ◽

Pentose Phosphate ◽

Clonal Line ◽

Swertia Chirayita ◽

Stimulation Of

Plants defense responses to abiotic stresses, including salinity stress, involve stimulation of defense related pathways such as biosynthesis of secondary metabolites and induction of endogenous antioxidant enzyme responses. In the present study, a single seed origin clonal line of Swertia chirayita inoculated with Lactobacillus plantarum (LP) was grown under different salinity levels. Control had no LP inoculation. S. chirayita inoculated with LP showed higher accumulation of proline, low proline dehydrogenase activity, up-regulation of pentose phosphate pathway, down-regulation of succinate dehydrogenase activity (Krebs cycle) and low total phenolic content with increased salt concentrations. In comparison, S. chirayita without LP adopted a different biochemical mechanism to counter salt stress (NaCl) by up-regulating both pentose phosphate pathway and Krebs cycle along with stimulation of phenolic biosynthesis. Guaiacol peroxidase (GPX) activity increased with and without LP treatment in response to increasing concentrations of salt. These results indicate that S. chirayita inoculated with LP exhibits a greater salinity stress tolerance than S. chirayita without LP by adopting a more energy efficient defense responses and potentially efficiently partitioning carbon flux between primary and secondary metabolism to counter salt induced oxidative stress.

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