Transcriptional activation of the IL‐6 gene in human contracting skeletal muscle: influence of muscle glycogen content

The effect of prolonged moderate-intensity exercise on human skeletal muscle AMP-activated protein kinase (AMPK)α1 and -α2 activity and acetyl-CoA carboxylase (ACCβ) and neuronal nitric oxide synthase (nNOSμ) phosphorylation was investigated. Seven active healthy individuals cycled for 30 min at a workload requiring 62.8 ± 1.3% of peak O2consumption (V˙o 2 peak) with muscle biopsies obtained from the vastus lateralis at rest and at 5 and 30 min of exercise. AMPKα1 activity was not altered by exercise; however, AMPKα2 activity was significantly ( P < 0.05) elevated after 5 min (∼2-fold), and further elevated ( P < 0.05) after 30 min (∼3-fold) of exercise. ACCβ phosphorylation was increased ( P < 0.05) after 5 min (∼18-fold compared with rest) and increased ( P< 0.05) further after 30 min of exercise (∼36-fold compared with rest). Increases in AMPKα2 activity were significantly correlated with both increases in ACCβ phosphorylation and reductions in muscle glycogen content. Fat oxidation tended ( P = 0.058) to increase progressively during exercise. Muscle creatine phosphate was lower ( P < 0.05), and muscle creatine, calculated free AMP, and free AMP-to-ATP ratio were higher ( P < 0.05) at both 5 and 30 min of exercise compared with those at rest. At 30 min of exercise, the values of these metabolites were not significantly different from those at 5 min of exercise. Phosphorylation of nNOSμ was variable, and despite the mean doubling with exercise, statistically significance was not achieved ( P = 0.304). Western blots indicated that AMPKα2 was associated with both nNOSμ and ACCβ consistent with them both being substrates of AMPKα2 in vivo. In conclusion, AMPKα2 activity and ACCβ phosphorylation increase progressively during moderate exercise at ∼60% of V˙o 2 peak in humans, with these responses more closely coupled to muscle glycogen content than muscle AMP/ATP ratio.

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Skeletal muscle glycogen content in patients with cirrhosis

Hepatology ◽

10.1002/hep.1840200121 ◽

1994 ◽

Vol 20 (1) ◽

pp. 135-141 ◽

Cited By ~ 10

Author(s):

Oliver Selberg ◽

Eva Radoch ◽

Gerhard Franz Walter ◽

Manfred James Müller

Keyword(s):

Skeletal Muscle ◽

Muscle Glycogen ◽

Glycogen Content ◽

Muscle Glycogen Content ◽

Skeletal Muscle Glycogen

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Assessment of Skeletal Muscle Glycogen Content in University Football Players before and after a Game

Medicine & Science in Sports & Exercise ◽

10.1249/01.mss.0000479081.80902.09 ◽

2015 ◽

Vol 47 ◽

pp. 867

Author(s):

Inigo San Millan ◽

John Hill

Keyword(s):

Skeletal Muscle ◽

Muscle Glycogen ◽

Glycogen Content ◽

Football Players ◽

Muscle Glycogen Content ◽

Skeletal Muscle Glycogen ◽

Before And After

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Influence of muscle glycogen availability on ERK1/2 and Akt signaling after resistance exercise in human skeletal muscle

Journal of Applied Physiology ◽

10.1152/japplphysiol.00110.2005 ◽

2005 ◽

Vol 99 (3) ◽

pp. 950-956 ◽

Cited By ~ 98

Author(s):

Andrew Creer ◽

Philip Gallagher ◽

Dustin Slivka ◽

Bozena Jemiolo ◽

William Fink ◽

...

Keyword(s):

Skeletal Muscle ◽

Resistance Exercise ◽

Muscle Glycogen ◽

Human Skeletal Muscle ◽

Glycogen Content ◽

Vastus Lateralis ◽

Akt Signaling ◽

Cellular Growth ◽

Muscle Glycogen Content ◽

Ribosomal S6 Kinase

Two pathways that have been implicated for cellular growth and development in response to muscle contraction are the extracellular signal-regulated kinase (ERK1/2) and Akt signaling pathways. Although these pathways are readily stimulated after exercise, little is known about how nutritional status may affect stimulation of these pathways in response to resistance exercise in human skeletal muscle. To investigate this, experienced cyclists performed 30 repetitions of knee extension exercise at 70% of one repetition maximum after a low (2%) or high (77%) carbohydrate (LCHO or HCHO) diet, which resulted in low or high (∼174 or ∼591 mmol/kg dry wt) preexercise muscle glycogen content. Muscle biopsies were taken from the vastus lateralis before, ∼20 s after, and 10 min after exercise. ERK1/2 and p90 ribosomal S6 kinase phosphorylation increased ( P ≤ 0.05) 10 min after exercise, regardless of muscle glycogen availability. Akt phosphorylation was elevated ( P < 0.05) 10 min after exercise in the HCHO trial but was unaffected after exercise in the LCHO trial. Mammalian target of rapamycin phosphorylation was similar to that of Akt during each trial; however, change or lack of change was not significant. In conclusion, the ERK1/2 pathway appears to be unaffected by muscle glycogen content. However, muscle glycogen availability appears to contribute to regulation of the Akt pathway, which may influence cellular growth and adaptation in response to resistance exercise in a low-glycogen state.

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Skeletal Muscle Glycogen Content at Rest and During Endurance Exercise in Humans: A Meta-Analysis

Sports Medicine ◽

10.1007/s40279-018-0941-1 ◽

2018 ◽

Vol 48 (9) ◽

pp. 2091-2102 ◽

Cited By ~ 23

Author(s):

José L. Areta ◽

Will G. Hopkins

Keyword(s):

Skeletal Muscle ◽

Endurance Exercise ◽

Muscle Glycogen ◽

Glycogen Content ◽

Meta Analysis ◽

Muscle Glycogen Content ◽

Skeletal Muscle Glycogen ◽

Exercise In Humans

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Hepatic and skeletal muscle glycogen content in rats treated with metformin and submitted to acute exercise by swimming

Revista Brasileira de Educação Física e Esporte ◽

10.11606/1807-5509201700020355 ◽

2018 ◽

Vol 31 (2) ◽

pp. 355

Author(s):

Vitor Alexandre Pezolato ◽

Marcos Almeida Marques ◽

Fabio Marcos Abreu ◽

Nataly Mendes Silva ◽

Ronaldo Júlio Baganha ◽

...

Keyword(s):

Skeletal Muscle ◽

Muscle Glycogen ◽

Acute Exercise ◽

Glycogen Content ◽

Muscle Glycogen Content ◽

Skeletal Muscle Glycogen

O objetivo deste estudo foi avaliar o comportamento das reservas glicogênicas de ratos, submetidos a uma condição de exercício agudo (50 minutos de natação na intensidade leve), após o tratamento com metformina. Quarenta ratos Wistar (180-200g) adultos foram divididos em quatro grupos (tratados ou não por quinze dias) e assim representados: Controle; Exercício agudo por natação (realizaram uma sessão de natação, sendo 50 minutos na intensidade leve); Tratado com metformina (receberam o fármaco metformina na dosagem de 1,4 mg/ml, durante o período experimental; Tratados com metformina e submetidos a condição exercício agudo por natação (receberam o fármaco metformina na dosagem de 1,4 mg/ml e realizaram uma sessão de natação, sendo 50 minutos na intensidade leve). O exercício agudo diminuiu as reservas glicogênicas, já os animais tratados com metformina, apresentaram um aumento em suas reservas glicogênicas musculares e hepáticas em relação ao grupo que realizou o exercício sem suplementação (p0,05). O tratamento com metformina promoveu melhora nas condições energéticas e menor resposta ao estresse, sugerindo ser uma importante ferramenta farmacológica para a potencialização da performance.

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Skeletal muscle GLUT-4 and glucose uptake during exercise in humans

Journal of Applied Physiology ◽

10.1152/jappl.1994.77.3.1565 ◽

1994 ◽

Vol 77 (3) ◽

pp. 1565-1568 ◽

Cited By ~ 17

Author(s):

G. McConell ◽

M. McCoy ◽

J. Proietto ◽

M. Hargreaves

Keyword(s):

Skeletal Muscle ◽

Oxygen Consumption ◽

Glucose Uptake ◽

Muscle Glycogen ◽

Protein Level ◽

Glycogen Content ◽

Citrate Synthase ◽

Vastus Lateralis ◽

Muscle Glycogen Content ◽

Glut 4

The present study examined the relationship between total skeletal muscle GLUT-4 protein level and glucose uptake during exercise. Eight active non-endurance-trained men cycled at 72 +/- 1% peak pulmonary oxygen consumption for 40 min, with rates of glucose appearance and disappearance (Rd) determined by utilizing a primed continuous infusion of [3–3H]glucose commencing 2 h before exercise. Muscle glycogen content and utilization, citrate synthase activity, and total GLUT-4 protein were measured on muscle biopsy samples obtained from the vastus lateralis. A direct relationship existed between preexercise muscle glycogen content and glycogen utilization during exercise (r = 0.76, P < 0.05). Citrate synthase activity and glucose Rd at the end of exercise averaged 21.9 +/- 3.0 mumol.min-1.g-1 and 27.3 +/- 2.5 mumol.kg-1.min-1, respectively. There was a direct correlation between citrate synthase activity and GLUT-4 protein (r = 0.78, P < 0.05); however, at the end of exercise, glucose Rd was inversely related to both GLUT-4 (r = -0.89, P < 0.01) and citrate synthase activity (r = -0.72, P < 0.05). Plasma insulin, which decreased during exercise, was not related to glucose Rd. In conclusion, glucose uptake during 40 min of exercise at 72% peak pulmonary oxygen consumption was inversely related to the total muscle GLUT-4 protein level. This suggests that factors other than the total GLUT-4 protein level are important in the regulation of glucose uptake during exercise.

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Effect of ginger extract ingestion on skeletal muscle glycogen contents and endurance exercise in male rats

Physical Activity and Nutrition ◽

10.20463/pan.2021.0010 ◽

2021 ◽

Vol 25 (2) ◽

pp. 15-19

Author(s):

Satoshi Hattori ◽

Naomi Omi ◽

Zhou Yang ◽

Moeka Nakamura ◽

Masahiro Ikemoto

Keyword(s):

Skeletal Muscle ◽

Exercise Capacity ◽

Muscle Glycogen ◽

Exercise Performance ◽

Glycogen Content ◽

Intermittent Exercise ◽

Endurance Capacity ◽

Ginger Extract ◽

Muscle Glycogen Content ◽

Skeletal Muscle Glycogen

[Purpose] Skeletal muscle glycogen is a determinant of endurance capacity for some athletes. Ginger is well known to possess nutritional effects, such as anti-diabetic effects. We hypothesized that ginger extract (GE) ingestion increases skeletal muscle glycogen by enhancing fat oxidation. Thus, we investigated the effect of GE ingestion on exercise capacity, skeletal muscle glycogen, and certain blood metabolites in exercised rats. [Methods] First, we evaluated the influence of GE ingestion on body weight and elevation of exercise performance in rats fed with different volumes of GE. Next, we measured the skeletal muscle glycogen content and free fatty acid (FFA) levels in GE-fed rats. Finally, we demonstrated that GE ingestion contributes to endurance capacity during intermittent exercise to exhaustion. [Results] We confirmed that GE ingestion increased exercise performance (p<0.05) and elevated the skeletal muscle glycogen content compared to the non- GE-fed (CE, control exercise) group before exercise (Soleus: p<0.01, Plantaris: p<0.01, Gastrocnemius: p<0.05). Blood FFA levels in the GE group were significantly higher than those in the CE group after exercise (p<0.05). Moreover, we demonstrated that exercise capacity was maintained in the CE group during intermittent exercise (p<0.05). [Conclusion] These findings indicate that GE ingestion increases skeletal muscle glycogen content and exercise performance through the upregulation of fat oxidation.

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The roles of IL-6 in the regulation of glucose homeostasis

Applied Physiology Nutrition and Metabolism ◽

10.1139/h08-105 ◽

2009 ◽

Vol 34 (1) ◽

pp. 83-84

Author(s):

Jenny E. Gusba

Keyword(s):

Skeletal Muscle ◽

Protein Kinase ◽

Muscle Contraction ◽

Glucose Transport ◽

Glucose Homeostasis ◽

Muscle Glycogen ◽

Glycogen Content ◽

Glycogen Resynthesis ◽

Muscle Glycogen Content ◽

Tnf Α

This thesis examined the roles of interleukin (IL)-6 in the regulation of glucose homeostasis, with a specific focus on skeletal muscle. Study 1 sought to determine whether muscle glycogen content is a stimulus for the production of IL-6, examining the periods during and after exercise. The relationship between IL-6 and muscle glycogen content was measured during similar bouts of exhaustive exercise on 2 occasions that resulted in large increases in muscle messenger (m)RNA for IL-6 and circulating levels of IL-6. On 1 occasion, subjects received carbohydrate during recovery to facilitate rates of glycogen resynthesis. During exercise, subjects performed similar bouts of exercise, such that differences in an individual’s glycogen levels between trials could be compared with differences in IL-6. No correlation was detected between the net change in glycogen content and the net change in plasma IL-6 or IL-6 mRNA from rest to exhaustion. Moreover, when the difference within subjects at exhaustion in IL-6 and glycogen was compared, there was no correlation between the 2 variables. During recovery, although carbohydrate intake significantly increased glycogen resynthesis, there was no change in postexercise IL-6 mRNA level or plasma IL-6 concentration. Therefore, glycogen was not the sole regulator of IL-6 production in skeletal muscle. Study 2 examined the direct effect of IL-6 and tumor necrosis factor (TNF)-α on glucose transport and the phosphorylation of key signalling proteins with or without insulin and during rodent muscle contraction. Under basal conditions, IL-6 increased glucose transport in association with an increase in 5′AMP-activated protein kinase (AMPK) and AS160 phosphorylation, but IL-6 decreased insulin-stimulated glucose transport via a reduction in phosphorylation of calcium–calmodulin-dependent protein kinase (CaMK)II and AS160. A novel finding generated from these experiments was the direct involvement of IL-6 in contraction-mediated glucose transport. In the case of muscle contraction, IL-6 was found to increase the phosphorylation of CaMKII and AS160. This research suggests that the activation of CaMKII is involved in the actions of IL-6 under insulin-stimulated and contraction-mediated conditions. Furthermore, AS160 was identified as a common signalling intermediate, influenced by IL-6. It also suggests that AS160 may be a point of convergence for multiple signalling pathways. Finally, the actions of TNF-α mimicked those of IL-6, except during contraction, where TNF-α had no significant effect on glucose transport and attenuated the effects of IL-6.

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