scholarly journals Gluconeogenesis and glycogen metabolism during development of Pacific abalone, Haliotis discus hannai

2020 ◽  
Vol 318 (3) ◽  
pp. R619-R633 ◽  
Author(s):  
Mugen Koyama ◽  
Fumiya Furukawa ◽  
Yuka Koga ◽  
Shohei Funayama ◽  
Suehiro Furukawa ◽  
...  
Keyword(s):  
Glycogen Synthase ◽  
Egg Yolk ◽  
Glycogen Metabolism ◽  
Glycogen Storage ◽  
Glucose Content ◽  
Pacific Abalone ◽  
Nutrient Sources ◽  
Haliotis Discus ◽  
Inhibition Of Glycolysis ◽  
Veliger Larvae

In lecithotrophic larvae, egg yolk nutrients are essential for development. Although yolk proteins and lipids are the major nutrient sources for most animal embryos and larvae, the contribution of carbohydrates to development has been less understood. In this study, we assessed glucose and glycogen metabolism in developing Pacific abalone, a marine gastropod mollusc caught and cultured in east Asia. We found that glucose and glycogen content gradually elevated in developing abalone larvae, and coincident expression increases of gluconeogenic genes and glycogen synthase suggested abalone larvae had activated gluconeogenesis and glycogenesis during this stage. At settling, however, glycogen sharply decreased, with concomitant increases in glucose content and expression of Pyg and G6pc, suggesting the settling larvae had enhanced glycogen conversion to glucose. A liquid chromatography-mass spectrometry (LC/MS)-based metabolomic approach that detected intermediates of these pathways further supported active metabolism of glycogen. Immunofluorescence staining and in situ hybridization suggested the digestive gland has an important role as glycogen storage tissue during settlement, while many other tissues also showed a capacity to metabolize glycogen. Finally, inhibition of glycolysis affected survival of the settling veliger larvae, revealing that glucose is, indeed, an important nutrient source in settling larvae. Our results suggest glucose and glycogen are required for proper energy balance in developing abalone and especially impact survival during settling.

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.

Liver and peripheral tissue glycogen metabolism in obese mice: effect of a mixed meal

1993 ◽  
Vol 265 (5) ◽  
pp. E743-E751
Author(s):  
C. Chen ◽  
P. F. Williams ◽  
I. D. Caterson
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Cardiac Muscle ◽  
White Adipose Tissue ◽  
Glycogen Content ◽  
Glycogen Synthase ◽  
Glycogen Metabolism ◽  
Glycogen Storage ◽  
Obese Mice ◽  
Entire Study

Glycogen metabolism in the liver, skeletal muscle, cardiac muscle, and white adipose tissue was studied in gold thioglucose (GTG) obese mice after fasting and during refeeding. Prolonged (48 h) fasted control and GTG mice were refed with standard laboratory diet for 24 h. During fasting and refeeding, the changes in glycogen content and the activity of glycogen synthase I and R and phosphorylase alpha in the liver were similar in lean and GTG mice. However, the glycogen storage in the livers from GTG mice was always greater than that in lean animals. In GTG mice the activity of liver glycogen synthase I and R was significantly higher than that in lean animals 3 and 6 h after refeeding. The activity of liver phosphorylase alpha in GTG mice was higher than that in lean mice after refeeding. There were no significant differences in the glycogen content of white adipose tissue, cardiac muscle, and skeletal muscle from lean and GTG mice during the entire study. The results of this study suggest that increased glycogen storage in the liver is a major alteration in nonoxidative glucose metabolism and contributes to the development of insulin resistance and glucose intolerance in GTG obese mice.

Abstract 3470: Deletion of Glycogen Synthase Kinase-3α (GKS-3α) Causes a Glycogen Storage Cardiomyopathy

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Jibin Zhou ◽  
Risto Kerkela ◽  
David Harris ◽  
Katrina MacAulay ◽  
Lisa Kocheritz ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Heart Development ◽  
Glycogen Synthase ◽  
Periodic Acid ◽  
Glycogen Metabolism ◽  
Glycogen Storage ◽  
Negative Regulator ◽  
Heart Weight ◽  
Lv Function ◽  
Gsk 3Β

Background: GSK-3 and its targets play critical roles in a wide array of processes including development and cancer. In mammalian cells there are two isoforms, α and β. GSK-3β is purported to be a negative regulator of cardiac hypertrophy, but this is based solely on over-expression approaches, and virtually nothing is known of the functions of GSK-3α. Methods: We generated mice deleted for GSK-3α. Heart development, as well as postnatal cardiac growth, glycogen metabolism, morphology, physiology, and ECG conduction invervals were examined. Age-matched wild type (WT) mice served as controls. Results: Heart development was normal, consistent with full compensation by GSK-3β for loss of GSK-3α during development. However, echocardiographic LV mass (in mg) was significantly increased in the KO compared to WT: 187.95 ± 35.05 vs 143.52 ± 23.94*. Heart weight (HW, mg) and HW/body weight ratio were also significantly increased in the KO: 186.73 ± 15.3* and 4.96 ± 0.38* for KO (n = 19); 146.33 ± 14.92 and 4.12 ± 0.27 for WT (n = 10). Thus deletion of GSK-3α leads to significant cardiac hypertrophy with aging. The underlying mechanism appears to be marked glycogen deposition seen with both Periodic acid-Schiff staining and transmission electron microscopy. Although LV function as assessed by echocardiography was normal at 4 months of age, invasive hemodynamic evaluation demonstrated a depressed response to isoproterenol infusion. ECG revealed a significantly shortened PR interval without pre-excitation. Conclusions: We demonstrate for the first time a striking isoform-specific role for GSK-3α in the heart, and that role is as a critical regulator of glycogen metabolism. Deletion of GSK-3α leads to a glycogen storage cardiomyopathy, sharing some features with that seen with mutations in AMP-activated protein kinase. These data suggest the possibility that mutations in, or alterations in activity of, GSK-3α could account for some cases of hypertrophic cardiomyopathy. (*, P < 0.01, KO vs. WT)

scholarly journals Mechanism of glycogen synthase inactivation and interaction with glycogenin

2021 ◽  
Author(s):  
Laura Marr ◽  
Dipsikha Biswas ◽  
Leonard A Daly ◽  
Christopher Browning ◽  
John Pollard ◽  
...  
Keyword(s):  
Glycogen Synthase ◽  
Glycogen Synthesis ◽  
Glycogen Metabolism ◽  
Glycogen Storage ◽  
Moderate Increase ◽  
Storage Diseases ◽  
Future Studies ◽  
Glycogen Storage Diseases ◽  
Structure Lead

The macromolecule glycogen is the major glucose reserve in eukaryotes and defects of glycogen metabolism and structure lead to glycogen storage diseases and neurodegeneration. Glycogenesis begins with self-glucosylation of glycogenin (GN), which recruits glycogen synthase (GS). GS is activated by glucose-6-phosphate (G6P) and inactivated by phosphorylation, but how these opposing processes are coupled is unclear. We provide the first structure of phosphorylated human GS-GN complex revealing an autoinhibited GS tetramer flanked by two GN dimers. Phosphorylated N- and C-terminal tails from two GS protomers converge to form dynamic "spike" regions, which are buttressed against GS regulatory helices. This keeps GS in a constrained "tense" conformation that is inactive and more resistant to G6P activation. Mutagenesis that weaken the interaction between the regulatory helix and phosphorylated tails leads to a moderate increase in basal/unstimulated GS activity, supporting the idea that phosphorylation contributes to GS inactivation by constraining GS inter-subunit movement. We propose that multivalent phosphorylation supports GS autoinhibition through interactions from a dynamic "spike" region, thus allowing a "tuneable rheostat" for regulating GS activity. Our structures of human GS-GN provide new insights into the regulation of glycogen synthesis, facilitating future studies of glycogen storage diseases.

scholarly journals Glycogen and its metabolism: some new developments and old themes

2012 ◽  
Vol 441 (3) ◽  
pp. 763-787 ◽  
Author(s):  
Peter J. Roach ◽  
Anna A. Depaoli-Roach ◽  
Thomas D. Hurley ◽  
Vincent S. Tagliabracci
Keyword(s):  
Glycogen Synthase ◽  
Three Dimensional ◽  
Glycogen Metabolism ◽  
Glycogen Storage ◽  
Genetically Engineered ◽  
Relative Importance ◽  
Lafora Disease ◽  
New Developments ◽  
Glycogen Accumulation ◽  
Genetically Engineered Mice

Glycogen is a branched polymer of glucose that acts as a store of energy in times of nutritional sufficiency for utilization in times of need. Its metabolism has been the subject of extensive investigation and much is known about its regulation by hormones such as insulin, glucagon and adrenaline (epinephrine). There has been debate over the relative importance of allosteric compared with covalent control of the key biosynthetic enzyme, glycogen synthase, as well as the relative importance of glucose entry into cells compared with glycogen synthase regulation in determining glycogen accumulation. Significant new developments in eukaryotic glycogen metabolism over the last decade or so include: (i) three-dimensional structures of the biosynthetic enzymes glycogenin and glycogen synthase, with associated implications for mechanism and control; (ii) analyses of several genetically engineered mice with altered glycogen metabolism that shed light on the mechanism of control; (iii) greater appreciation of the spatial aspects of glycogen metabolism, including more focus on the lysosomal degradation of glycogen; and (iv) glycogen phosphorylation and advances in the study of Lafora disease, which is emerging as a glycogen storage disease.

Identification of growth-related SNPs and genes in the genome of the Pacific abalone (Haliotis discus hannai) using GWAS

Aquaculture ◽  
2021 ◽  
Vol 541 ◽  
pp. 736820
Author(s):  
Wenzhu Peng ◽  
Feng Yu ◽  
Yiyu Wu ◽  
Yifang Zhang ◽  
Chengkuan Lu ◽  
...  
Keyword(s):  
Haliotis Discus Hannai ◽  
Pacific Abalone ◽  
The Pacific ◽  
Haliotis Discus ◽  
Abalone Haliotis Discus

scholarly journals Norepinephrine Regulation of Ventromedial Hypothalamic Nucleus Astrocyte Glycogen Metabolism

2021 ◽  
Vol 22 (2) ◽  
pp. 759
Author(s):  
Karen P. Briski ◽  
Mostafa M. H. Ibrahim ◽  
A. S. M. Hasan Mahmood ◽  
Ayed A. Alshamrani
Keyword(s):  
Alternative Energy ◽  
Glycogen Synthase ◽  
Glycogen Metabolism ◽  
Receptor Expression ◽  
Hypothalamic Nucleus ◽  
Control Structures ◽  
Ventromedial Hypothalamic Nucleus ◽  
Glycogen Reserve ◽  
Noradrenergic Modulation ◽  
The Brain

The catecholamine norepinephrine (NE) links hindbrain metabolic-sensory neurons with key glucostatic control structures in the brain, including the ventromedial hypothalamic nucleus (VMN). In the brain, the glycogen reserve is maintained within the astrocyte cell compartment as an alternative energy source to blood-derived glucose. VMN astrocytes are direct targets for metabolic stimulus-driven noradrenergic signaling due to their adrenergic receptor expression (AR). The current review discusses recent affirmative evidence that neuro-metabolic stability in the VMN may be shaped by NE influence on astrocyte glycogen metabolism and glycogen-derived substrate fuel supply. Noradrenergic modulation of estrogen receptor (ER) control of VMN glycogen phosphorylase (GP) isoform expression supports the interaction of catecholamine and estradiol signals in shaping the physiological stimulus-specific control of astrocyte glycogen mobilization. Sex-dimorphic NE control of glycogen synthase and GP brain versus muscle type proteins may be due, in part, to the dissimilar noradrenergic governance of astrocyte AR and ER variant profiles in males versus females. Forthcoming advances in the understanding of the molecular mechanistic framework for catecholamine stimulus integration with other regulatory inputs to VMN astrocytes will undoubtedly reveal useful new molecular targets in each sex for glycogen mediated defense of neuronal metabolic equilibrium during neuro-glucopenia.

Metabolic effects of oral fructose in the liver of fasted rats

1984 ◽  
Vol 247 (4) ◽  
pp. E505-E512 ◽  
Author(s):  
C. B. Niewoehner ◽  
D. P. Gilboe ◽  
G. A. Nuttall ◽  
F. Q. Nuttall
Keyword(s):  
Uric Acid ◽  
Portal Vein ◽  
Hepatic Vein ◽  
Glycogen Synthase ◽  
Control Level ◽  
Liver Glycogen ◽  
Glycogen Storage ◽  
Metabolic Effects ◽  
Serum Triglycerides ◽  
Fasted Rats

Twenty-four-hour-fasted rats were given fructose (4 g/kg) by gavage. Fructose absorption and the portal vein, aorta, and hepatic vein plasma fructose, glucose, lactate, and insulin concentrations as well as liver fructose and fructose 1-P, glucose, glucose 6-P, UDPglucose, lactate, pyruvate, ATP, ADP, AMP, inorganic phosphate (Pi), cAMP, and Mg2+, and glycogen synthase I and phosphorylase alpha were measured at 10, 20, 30, 40, 60 and 120 min after gavage. Liver and muscle glycogen and serum uric acid and triglycerides also were measured. Fifty-nine percent of the fructose was absorbed in 2 h. There were modest increases in plasma and hepatic fructose, glucose, and lactate and in plasma insulin. Concentrations in the portal vein, aorta, and hepatic vein plasma indicate rapid removal of fructose and lactate by the liver and a modest increase in production of glucose. The source of the increase in plasma lactate is uncertain. Hepatic glucose 6-P increased twofold; UDPglucose rose transiently and then decreased below the control level. Fructose 1-P increased linearly to a concentration of 3.3 mumol/g wet wt by 120 min. There was no change in ATP, ADP, AMP, cAMP, Pi, or Mg2+. Serum triglycerides and uric acid were unchanged. Glycogen synthase was activated by 20 min without a change in phosphorylase alpha. This occurred with a fructose dose that did not significantly increase either the liver glucose or fructose concentrations. Liver glycogen increased linearly after 20 min, and glycogen storage was equal in liver (38.4%) and muscle (36.5%).(ABSTRACT TRUNCATED AT 250 WORDS)

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