scholarly journals Effect of hypoglycemia on brain glycogen metabolism in vivo

2003 ◽  
Vol 72 (1) ◽  
pp. 25-32 ◽  
Author(s):  
In-Young Choi ◽  
Elizabeth R. Seaquist ◽  
Rolf Gruetter
Keyword(s):  
Glycogen Metabolism ◽  
Brain Glycogen

scholarly journals Human brain glycogen content and metabolism: implications on its role in brain energy metabolism

2007 ◽  
Vol 292 (3) ◽  
pp. E946-E951 ◽  
Author(s):  
Gülin Öz ◽  
Elizabeth R. Seaquist ◽  
Anjali Kumar ◽  
Amy B. Criego ◽  
Luke E. Benedict ◽  
...  
Keyword(s):  
Human Brain ◽  
Glycogen Content ◽  
Visual Stimulation ◽  
Occipital Lobe ◽  
Glycogen Metabolism ◽  
Adult Brain ◽  
Brain Glycogen ◽  
Free Glucose ◽  
Time Courses

The adult brain relies on glucose for its energy needs and stores it in the form of glycogen, primarily in astrocytes. Animal and culture studies indicate that brain glycogen may support neuronal function when the glucose supply from the blood is inadequate and/or during neuronal activation. However, the concentration of glycogen and rates of its metabolism in the human brain are unknown. We used in vivo localized 13C-NMR spectroscopy to measure glycogen content and turnover in the human brain. Nine healthy volunteers received intravenous infusions of [1-13C]glucose for durations ranging from 6 to 50 h, and brain glycogen labeling and washout were measured in the occipital lobe for up to 84 h. The labeling kinetics suggest that turnover is the main mechanism of label incorporation into brain glycogen. Upon fitting a model of glycogen metabolism to the time courses of newly synthesized glycogen, human brain glycogen content was estimated at ∼3.5 μmol/g, i.e., three- to fourfold higher than free glucose at euglycemia. Turnover of bulk brain glycogen occurred at a rate of 0.16 μmol·g−1·h−1, implying that complete turnover requires 3–5 days. Twenty minutes of visual stimulation ( n = 5) did not result in detectable glycogen utilization in the visual cortex, as judged from similar [13C]glycogen levels before and after stimulation. We conclude that the brain stores a substantial amount of glycogen relative to free glucose and metabolizes this store very slowly under normal physiology.

Imaging liver and brain glycogen metabolism at the nanometer scale

2015 ◽  
Vol 11 (1) ◽  
pp. 239-245 ◽  
Author(s):  
Yuhei Takado ◽  
Graham Knott ◽  
Bruno M. Humbel ◽  
Stéphane Escrig ◽  
Mojgan Masoodi ◽  
...  
Keyword(s):  
Glycogen Metabolism ◽  
Nanometer Scale ◽  
Brain Glycogen

Brain glycogen metabolism: A possible link between sleep disturbances, headache and depression

2021 ◽  
Vol 59 ◽  
pp. 101449
Author(s):  
J-M. Petit ◽  
E. Eren-Koçak ◽  
H. Karatas ◽  
P. Magistretti ◽  
T. Dalkara
Keyword(s):  
Sleep Disturbances ◽  
Glycogen Metabolism ◽  
Brain Glycogen

scholarly journals A comparison of in vivo 13 C MR brain glycogen quantification at 9.4 and 14.1 T

2011 ◽  
Vol 67 (6) ◽  
pp. 1523-1527 ◽  
Author(s):  
Ruud B. van Heeswijk ◽  
Yves Pilloud ◽  
Florence D. Morgenthaler ◽  
Rolf Gruetter
Keyword(s):  
Brain Glycogen ◽  
Mr Brain

Preclinical Research in McArdle Disease: A Review of Research Models and Therapeutic Strategies

Genes ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 74
Author(s):  
Mónica Villarreal-Salazar ◽  
Astrid Brull ◽  
Gisela Nogales-Gadea ◽  
Antoni L. Andreu ◽  
Miguel A. Martín ◽  
...  
Keyword(s):  
Clinical Symptoms ◽  
Autosomal Recessive Disorder ◽  
Glycogen Metabolism ◽  
Preclinical Models ◽  
Preclinical Research ◽  
Mcardle Disease ◽  
Invasive Techniques ◽  
Insight Into

McArdle disease is an autosomal recessive disorder of muscle glycogen metabolism caused by pathogenic mutations in the PYGM gene, which encodes the skeletal muscle-specific isoform of glycogen phosphorylase. Clinical symptoms are mainly characterized by transient acute “crises” of early fatigue, myalgia and contractures, which can be accompanied by rhabdomyolysis. Owing to the difficulty of performing mechanistic studies in patients that often rely on invasive techniques, preclinical models have been used for decades, thereby contributing to gain insight into the pathophysiology and pathobiology of human diseases. In the present work, we describe the existing in vitro and in vivo preclinical models for McArdle disease and review the insights these models have provided. In addition, despite presenting some differences with the typical patient’s phenotype, these models allow for a deep study of the different features of the disease while representing a necessary preclinical step to assess the efficacy and safety of possible treatments before they are tested in patients.

Lipid and glycogen metabolism in the hypoxic heart: effects of epinephrine

1975 ◽  
Vol 229 (4) ◽  
pp. 885-889 ◽  
Author(s):  
Crass MF ◽  
GM Pieper
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Fatty Acid Oxidation ◽  
Glycogen Metabolism ◽  
Acid Oxidation ◽  
Triglyceride Fatty Acid ◽  
Rat Hearts ◽  
Perfused Rat Hearts

The metabolism of cardiac lipids and glycogen in hypoxic and well-oxygenated perfused rat hearts was studied in the presence or absence of epinephrine. Heart lipids were pre-labeled in vivo with [1-14C]palmitate. Triglyceride disappearance (measured chemically and radiochemically) was observed in well-oxygenated hearts and was stimulated by epinephrine (4.1 X 10(-7)M). Utilization of tissue triglycerides was inhibited in hypoxic hearts in the presence or absence of added epinephrine. Hypoxia resulted in a small increase in tissue 14C-free fatty acids and inhibition of 14C-labeled triglyceride fatty acid oxidation. Epinephrine had no stimulatory effect on fatty acid oxidation in hypoxic hearts. Utilization of 14C-labeled phospholipids (and total phospholipids) was similar in well-oxygenated and hypoxic hearts with or without added epinephrine. These results suggested that the antilipolytic effects of hypoxia were predominant over the lipolytic effects of epinephrine. Glycogenolysis was stimulated threefold by epinephrine in well-oxygenated hearts. Hypoxia alone was a potent stimulus to glycogenolysis. Addition of epinephrine to perfusates of hypoxic hearts resulted in a slight enhancement of glycogenolysis.

scholarly journals Glycogen serves as an energy source that maintains astrocyte cell proliferation in the neonatal telencephalon

2016 ◽  
Vol 37 (6) ◽  
pp. 2294-2307 ◽  
Author(s):  
Hitoshi Gotoh ◽  
Tadashi Nomura ◽  
Katsuhiko Ono
Keyword(s):  
Energy Source ◽  
Cell Proliferation ◽  
Glycogen Phosphorylase ◽  
Cell Cycle Progression ◽  
Neuronal Development ◽  
Kinase Inhibitors ◽  
Primary Cultures ◽  
Glycogen Metabolism ◽  
Radial Glial Cells

Large amounts of energy are required when cells undergo cell proliferation and differentiation for mammalian neuronal development. Early neonatal mice face transient starvation and use stored energy for survival or to support development. Glycogen is a branched polysaccharide that is formed by glucose, and serves as an astrocytic energy store for rapid energy requirements. Although it is present in radial glial cells and astrocytes, the role of glycogen during development remains unclear. In the present study, we demonstrated that glycogen accumulated in glutamate aspartate transporter (GLAST)+ astrocytes in the subventricular zone and rostral migratory stream. Glycogen levels markedly decreased after birth due to the increase of glycogen phosphorylase, an essential enzyme for glycogen metabolism. In primary cultures and in vivo, the inhibition of glycogen phosphorylase decreased the proliferation of astrocytic cells. The number of cells in the G1 phase increased in combination with the up-regulation of cyclin-dependent kinase inhibitors or down-regulation of the phosphorylation of retinoblastoma protein (pRB), a determinant for cell cycle progression. These results suggest that glycogen accumulates in astrocytes located in specific areas during the prenatal stage and is used as an energy source to maintain normal development in the early postnatal stage.

scholarly journals Transgenic overexpression of protein targeting to glycogen markedly increases adipocytic glycogen storage in mice

2007 ◽  
Vol 292 (3) ◽  
pp. E952-E963 ◽  
Author(s):  
Michael J. Jurczak ◽  
Arpad M. Danos ◽  
Victoria R. Rehrmann ◽  
Margaret B. Allison ◽  
Cynthia C. Greenberg ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Glycogen Synthase ◽  
Glycogen Synthesis ◽  
Transgenic Animals ◽  
Glycogen Metabolism ◽  
Glycogen Storage ◽  
Fatty Acid Binding ◽  
Fat Depots

Adipocytes express the rate-limiting enzymes required for glycogen metabolism and increase glycogen synthesis in response to insulin. However, the physiological function of adipocytic glycogen in vivo is unclear, due in part to the low absolute levels and the apparent biophysical constraints of adipocyte morphology on glycogen accumulation. To further study the regulation of glycogen metabolism in adipose tissue, transgenic mice were generated that overexpressed the protein phosphatase-1 (PP1) glycogen-targeting subunit (PTG) driven by the adipocyte fatty acid binding protein (aP2) promoter. Exogenous PTG was detected in gonadal, perirenal, and brown fat depots, but it was not detected in any other tissue examined. PTG overexpression resulted in a modest redistribution of PP1 to glycogen particles, corresponding to a threefold increase in the glycogen synthase activity ratio. Glycogen synthase protein levels were also increased twofold, resulting in a combined greater than sixfold enhancement of basal glycogen synthase specific activity. Adipocytic glycogen levels were increased 200- to 400-fold in transgenic animals, and this increase was maintained to 1 yr of age. In contrast, lipid metabolism in transgenic adipose tissue was not significantly altered, as assessed by lipogenic rates, weight gain on normal or high-fat diets, or circulating free fatty acid levels after a fast. However, circulating and adipocytic leptin levels were doubled in transgenic animals, whereas adiponectin expression was unchanged. Cumulatively, these data indicate that murine adipocytes are capable of storing far higher levels of glycogen than previously reported. Furthermore, these results were obtained by overexpression of an endogenous adipocytic protein, suggesting that mechanisms may exist in vivo to maintain adipocytic glycogen storage at a physiological set point.

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