Hexose monophosphate shunt, the role of its metabolites and associated disorders: A review

2019 ◽  
Vol 234 (9) ◽  
pp. 14473-14482 ◽  
Author(s):  
Muhammad Akram ◽  
Syed Muhammad Ali Shah ◽  
Naveed Munir ◽  
Muhammad Daniyal ◽  
Imtiaz Mahmood Tahir ◽  
...  
Keyword(s):  
Hexose Monophosphate ◽  
Hexose Monophosphate Shunt

Impact of nitric oxide on macrophage glucose metabolism and glyceraldehyde-3-phosphate dehydrogenase activity

1995 ◽  
Vol 268 (3) ◽  
pp. C669-C675 ◽  
Author(s):  
R. B. Mateo ◽  
J. S. Reichner ◽  
B. Mastrofrancesco ◽  
D. Kraft-Stolar ◽  
J. E. Albina
Keyword(s):  
Nitric Oxide ◽  
Glucose Metabolism ◽  
Dehydrogenase Activity ◽  
Cell Activation ◽  
Glycolytic Flux ◽  
No Production ◽  
Hexose Monophosphate ◽  
Hexose Monophosphate Shunt ◽  
Conflicting Evidence

Conflicting evidence has been presented regarding the role of nitric oxide (NO) in the regulation of cellular glucose metabolism. While it enhances glucose uptake and utilization through glycolysis and the hexose monophosphate shunt in macrophages and other cells, NO also inhibits glyceraldehyde-3-phosphate dehydrogenase, an enzyme catalyzing the metabolism of intermediates generated by both pathways. Indeed, it has been proposed that NO modulates glycolytic flux by suppressing glyceraldehyde-3-phosphate dehydrogenase activity. To establish the relative impact of these apparently incompatible actions, the effects of exogenous or endogenous NO on different aspects of glucose metabolism in macrophages were investigated. Cell activation increased NO production, maximal glyceraldehyde-3-phosphate dehydrogenase activity, and glucose metabolism through glycolysis and the hexose monophosphate shunt. NO generated endogenously or from S-nitroso-N-acetylpenicillamine (> 500 microM) reduced maximal glyceraldehyde-3-phosphate dehydrogenase activity in culture. The suppression of maximal glyceraldehyde-3-phosphate dehydrogenase coincided with decreased lactate accumulation only in concert with a marked loss of viable cells in the cultures. The maximal glyceraldehyde-3-phosphate dehydrogenase activity did not appear to be rate limiting for glucose metabolism when moderately inhibited by NO. A potential causal relationship between profound glyceraldehyde-3-phosphate dehydrogenase inhibition and cell death remains to be established.

Cytoplasmic pH regulation in phorbol ester-activated human neutrophils

1986 ◽  
Vol 251 (1) ◽  
pp. C55-C65 ◽  
Author(s):  
S. Grinstein ◽  
W. Furuya
Keyword(s):  
Metabolic Pathways ◽  
Phorbol Esters ◽  
Ph Regulation ◽  
Human Neutrophils ◽  
Hexose Monophosphate ◽  
Cytoplasmic Ph ◽  
Extracellular Acidification ◽  
Hexose Monophosphate Shunt ◽  
Activated Neutrophils ◽  
Cytoplasmic Acidification

Activation of neutrophils by 12-O-tetradecanoylphorbol-13-acetate (TPA) is accompanied by an initial cytoplasmic acidification, followed by an alkalinizing phase due to Na+-H+ countertransport. The source of the acidification, which is fully expressed by activation with TPA in Na+-free or amiloride-containing media, was investigated. The acidification phase was detected also in degranulated and enucleated cytoplasts, ruling out a major contribution by the nucleus or secretory vesicles. Cytoplasmic acidification was found to be associated with an extracellular acidification, suggesting metabolic generation of H+. Two principal metabolic pathways are stimulated in activated neutrophils: the reduction of O2 by NADPH-oxidase and the hexose monophosphate shunt. A good correlation was found between the activity of these pathways and the changes in cytoplasmic pH. Inhibition of superoxide synthesis prevented the TPA-induced cytoplasmic acidification. Moreover, activation of the hexose monophosphate shunt with permeable NADPH-oxidizing agents (in the absence of TPA) also produced a cytoplasmic acidification. Cytoplasmic acidification was also elicited by exogenous diacylglycerol and by other beta-phorbol diesters, which are activators of the kinase, but not by unesterified phorbol or by alpha-phorbol diesters, which are biologically inactive. The results suggest that the cytoplasmic acidification induced by phorbol esters in neutrophils reflects accumulation of H+ liberated during the metabolic burst that follows activation.

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