scholarly journals The Key Role of Anaplerosis and Cataplerosis for Citric Acid Cycle Function

2002 ◽  
Vol 277 (34) ◽  
pp. 30409-30412 ◽  
Author(s):  
Oliver E. Owen ◽  
Satish C. Kalhan ◽  
Richard W. Hanson
1995 ◽  
Vol 269 (1) ◽  
pp. E61-E66
Author(s):  
J. M. Egan ◽  
T. E. Henderson ◽  
M. Bernier

The present study was undertaken to define the role of L-arginine (L-Arg) in glucose metabolism in differentiated 3T3-L1 adipocytes in culture. L-Arg alone had no effect on 2-deoxyglucose uptake or basal glycogen synthesis, but this amino acid increased by 153 +/- 10% (P < 0.01) the incorporation of glucose into glycogen in insulin-treated cells. L-Glutamate (L-Glu), a major metabolite of L-Arg, also enhanced insulin-stimulated glycogen synthesis. The response to insulin was not altered by L-lysine (L-Lys), but the effect of L-Arg was markedly attenuated by L-Lys. Cell incubation with L-Arg markedly enhanced arginase-mediated urea synthesis, whereas L-Lys abolished this response. The stimulatory effect of L-Arg on insulin-stimulated glycogen synthesis did not appear to be accounted for by the generation of polyamines or the production of nitric oxide, both potentially derived from the enzymatic conversion of L-Arg. In the presence of insulin, cellular ATP levels were significantly increased by L-Arg, L-Glu, and L-Lys as well. These data suggest that metabolic degradation of L-Arg not related to citric acid cycle activity is important in the mechanism by which L-Arg enhances insulin-stimulated glycogen synthesis.


Author(s):  
Lina Wang ◽  
Donghai Cui ◽  
Xueyuan Zhao ◽  
Miao He

Biomolecules ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1068 ◽  
Author(s):  
Joséphine Zangari ◽  
Francesco Petrelli ◽  
Benoît Maillot ◽  
Jean-Claude Martinou

Pyruvate, the end product of glycolysis, plays a major role in cell metabolism. Produced in the cytosol, it is oxidized in the mitochondria where it fuels the citric acid cycle and boosts oxidative phosphorylation. Its sole entry point into mitochondria is through the recently identified mitochondrial pyruvate carrier (MPC). In this review, we report the latest findings on the physiology of the MPC and we discuss how a dysfunctional MPC can lead to diverse pathologies, including neurodegenerative diseases, metabolic disorders, and cancer.


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