Glucose-6-phosphate dehydrogenase activity and NADPH/NADP+ ratio in liver and pancreas are dependent on the severity of hyperglycemia in rat

Díaz‐Flores, Margarita; Hernández, Miguel; Galván, Rosa; Gutiérrez, Margarita; Durán‐Reyes, Genoveva; Medina-Navarro, Rafael; Pascoe-Lira, Dalila; Ortega-Camarillo, Clara; Vilar-Rojas, C; Crúz, Miguel A.; Baiza-Gutman, Luís Arturo

doi:10.1016/j.lfs.2005.10.022

Cited by 69 publications

(47 citation statements)

References 45 publications

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“…The oxPPP is the principal source for cytosolic NADPH in the liver [60], and its activity correlates linearly with the NADPH/NADP + ratio in rat liver [61]. The higher oxPPP flux in the GK-overexpressing cell lines therefore suggests that GK overexpression causes a higher cytosolic NADPH demand.…”

Section: Discussionmentioning

confidence: 96%

“…This leads to the interesting hypothesis that the enhanced oxPPP in the GK-overexpressing cell lines may contribute toward activating glucocorticoids and therefore toward the ASTP activity of GK. Finally, the hepatic levels of GSH, the principal intracellular antioxidant in the mammalian liver, are mainly dependent on NADPH generation by the oxPPP [60]. However, whether this has a connection with GK requires further investigation.…”

Section: Discussionmentioning

confidence: 99%

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Global metabolic effects of glycerol kinase overexpression in rat hepatoma cells

Sriram

Rahib

et al. 2008

Molecular Genetics and Metabolism

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Glycerol kinase has several diverse activities in mammalian cells. Glycerol kinase deficiency is a complex, single-gene, inborn error of metabolism wherein no genotype-phenotype correlation has been established. Since glycerol kinase has been suggested to exhibit additional activities than glycerol phosphorylation, expression level perturbation in this enzyme may affect cellular physiology globally. To investigate this possibility, we conducted metabolic investigations of wild type and two glycerol kinase-overexpressing H4IIE rat hepatoma cell lines constructed in this study. The glycerol kinase-overexpressing cell lines exhibited a significantly higher consumption of carbon sources per cell, suggesting excess carbon expenditure. Furthermore, we quantified intracellular metabolic fluxes by employing stable isotope ( 13 C) labeling with a mathematically designed substrate mixture, gas chromatography-mass spectrometry, and comprehensive isotopomer balancing. This flux analysis revealed that the pentose phosphate pathway flux in the glycerol kinase-overexpressing cell lines was two-fold higher than that in the wild type, in addition to subtler flux changes in other pathways of carbohydrate metabolism. Furthermore, the activity and transcript level of the lipogenic enzyme glucose-6-phosphate dehydrogenase, the rate-limiting enzyme of the pentose phosphate pathway, were also about two-fold higher than that of the wild type; these data corroborate the flux analysis results. This study shows that glycerol kinase affects carbon metabolism globally, possibly through its additional functions, and highlights glycerol kinase's multifaceted role in cellular physiology.

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Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

Global metabolic effects of glycerol kinase overexpression in rat hepatoma cells

Sriram

Rahib

et al. 2008

Molecular Genetics and Metabolism

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“…Beside, some authors stated that a defect in the antioxidant defense mechanisms and increased free radical production caused the oxidative damage brought about by dietary fructose 76 . In addition, it was reported that hyperglycemia was associated with decreased plasma insulin, glucose-6-PDH activity in plasma and liver, NADPH/NADP ratio and glutathione levels in the liver and pancreas 77 .…”

Section: Discussionmentioning

confidence: 99%

Potential Protective Effects of Nigella Sativa and Allium Sativum Against Fructose-Induced Metabolic Syndrome in Rats

Al-Rasheed

Bassiouni

et al. 2014

J. Oleo Sci.

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“…(Dzyakanchuk et al 2008). It means that the in vivo set point of the NADPH-NADP C redox couple is much more reduced in the ER lumen than in the cytosol (Díaz-Flores et al 2006, Pollak et al 2007, Panten & Rustenbeck 2008. H6PD is more resistant to feedback inhibition by NADPH than its cytosolic counterpart glucose-6-phosphate dehydrogenase (Oka et al 1981), which allows the almost complete reduction of the ER luminal pyridine nucleotide pool.…”

Section: Hsd11b1 Activity Is Determined By the [Nadph]/[nadp C ] Ratiomentioning

confidence: 99%

Hexose-6-phosphate dehydrogenase: linking endocrinology and metabolism in the endoplasmic reticulum

Bánhegyi¹,

Csala²,

Benedetti³

2008

Journal of Molecular Endocrinology

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Hexose-6-phosphate dehydrogenase (H6PD) got into the focus of interest due to its role in the prereceptorial activation of glucocorticoids, which has been implicated in the pathomechanism of metabolic syndrome. Genetic observations, results gained in H6PD knockout mice, and studies on differentiating adipocytes demonstrated the importance of the enzyme in metabolic regulation. A nutrient-sensing function can be postulated for the enzyme, which links metabolism to endocrinology in the endoplasmic reticulum. This review provides an overview of the recent developments concerning the enzyme and its impact on various branches of the intermediary metabolism, which make it an important subject for the research on obesity, diabetes, and metabolic syndrome.

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Glucose-6-phosphate dehydrogenase activity and NADPH/NADP+ ratio in liver and pancreas are dependent on the severity of hyperglycemia in rat

Cited by 69 publications

References 45 publications

Global metabolic effects of glycerol kinase overexpression in rat hepatoma cells

Global metabolic effects of glycerol kinase overexpression in rat hepatoma cells

Potential Protective Effects of Nigella Sativa and Allium Sativum Against Fructose-Induced Metabolic Syndrome in Rats

Hexose-6-phosphate dehydrogenase: linking endocrinology and metabolism in the endoplasmic reticulum

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