scholarly journals Muscle glycogen and metabolic regulation

2004 ◽  
Vol 63 (2) ◽  
pp. 217-220 ◽  
Author(s):  
Mark Hargreaves
Keyword(s):  
Muscle Glycogen ◽  
Insulin Action ◽  
Metabolic Regulation ◽  
Strenuous Exercise ◽  
Glycogen Depletion ◽  
Excitation Contraction Coupling ◽  
Glycogen Resynthesis ◽  
Contraction Coupling ◽  
Cellular Processes ◽  
Exercise Induced

Muscle glycogen is an important fuel for contracting skeletal muscle during prolonged strenuous exercise, and glycogen depletion has been implicated in muscle fatigue. It is also apparent that glycogen availability can exert important effects on a range of metabolic and cellular processes. These processes include carbohydrate, fat and protein metabolism during exercise, post-exercise glycogen resynthesis, excitation–contraction coupling, insulin action and gene transcription. For example, low muscle glycogen is associated with reduced muscle glycogenolysis, increased glucose and NEFA uptake and protein degradation, accelerated glycogen resynthesis, impaired excitation–contraction coupling, enhanced insulin action and potentiation of the exercise-induced increases in transcription of metabolic genes. Future studies should identify the mechanisms underlying, and the functional importance of, the association between glycogen availability and these processes.

Glycogen resynthesis in leg muscles of rats during exercise

1984 ◽  
Vol 247 (5) ◽  
pp. R880-R883 ◽  
Author(s):  
S. H. Constable ◽  
J. C. Young ◽  
M. Higuchi ◽  
J. O. Holloszy
Keyword(s):  
Muscle Glycogen ◽  
Prolonged Exercise ◽  
Liver Glycogen ◽  
Treadmill Running ◽  
Moderate Intensity ◽  
Glycogen Depletion ◽  
Moderate Intensity Exercise ◽  
Glycogen Resynthesis ◽  
Leg Muscles ◽  
Insulin In Plasma

This study was undertaken to determine whether glycogen resynthesis can occur in glycogen-depleted muscles in response to glucose feeding during prolonged exercise. Rats were exercised for 40 min with a treadmill running program designed to deplete muscle glycogen. One group was studied immediately after the glycogen-depletion exercise. A second group was given 1 g glucose by stomach tube and exercised for an additional 90 min at a running speed of 22 m/min on a treadmill set at an 8 degree incline; they were given additional 1-g glucose feedings after 30 and 60 min of running. The initial 40-min run resulted in liver glycogen depletion, large decreases in plasma glucose and insulin concentrations, and a marked lowering of muscle glycogen. The glucose feedings resulted in greater than twofold increases in the concentrations of glucose and insulin in plasma, and of glycogen in leg muscles, during the 90 min of running. No repletion of liver glycogen occurred. These results provide evidence that glycogen resynthesis can occur in glycogen-depleted muscle despite continued moderate intensity exercise if sufficient glucose is made available.

scholarly journals Effect of green tea extract supplementation on glycogen replenishment in exercised human skeletal muscle

2017 ◽  
Vol 117 (10) ◽  
pp. 1343-1350 ◽  
Author(s):  
Tsen-Wei Tsai ◽  
Chia-Chen Chang ◽  
Su-Fen Liao ◽  
Yi-Hung Liao ◽  
Chien-Wen Hou ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Content ◽  
Green Tea ◽  
Muscle Glycogen ◽  
Human Skeletal Muscle ◽  
Recovery Period ◽  
Glycogen Resynthesis ◽  
Postexercise Recovery ◽  
Exercise Induced ◽  
Tea Extract

AbstractThe purpose of this study was to investigate the effects of 8-week green tea extract (GTE) supplementation on promoting postexercise muscle glycogen resynthesis and systemic energy substrate utilisation in young college students. A total of eight healthy male participants (age: 22·0 (se 1·0) years, BMI: 24·2 (se 0·7) kg/m2, VO2max: 43·2 (se 2·4) ml/kg per min) participated in this study. GTE (500 mg/d for 8 weeks) was compared with placebo in participants in a double-blind/placebo-controlled and crossover study design with an 8-week washout period. Thereafter, all participants performed a 60-min cycling exercise (75 % VO2max) and consumed a carbohydrate-enriched meal immediately after exercise. Vastus lateralis muscle samples were collected immediately (0 h) and 3 h after exercise, and blood and gaseous samples were collected during the 3-h postexercise recovery period. An 8-week oral GTE supplementation had no effects on further promoting muscle glycogen resynthesis in exercised human skeletal muscle, but the exercise-induced muscle GLUT type 4 (GLUT4) protein content was greater in the GTE supplementation trial (P<0·05). We observed that, during the postexercise recovery period, GTE supplementation elicited an increase in energy reliance on fat oxidation compared with the placebo trial (P<0·05), although there were no differences in blood glucose and insulin responses between the two trials. In summary, 8-week oral GTE supplementation increases postexercise systemic fat oxidation and exercise-induced muscle GLUT4 protein content in response to an acute bout of endurance exercise. However, GTE supplementation has no further benefit on promoting muscle glycogen resynthesis during the postexercise period.

scholarly journals Effect of muscle glycogen depletion on in vivo insulin action in man.

1983 ◽  
Vol 72 (5) ◽  
pp. 1605-1610 ◽  
Author(s):  
C Bogardus ◽  
P Thuillez ◽  
E Ravussin ◽  
B Vasquez ◽  
M Narimiga ◽  
...  
Keyword(s):  
Muscle Glycogen ◽  
Insulin Action ◽  
Glycogen Depletion

Exercise and glycogen depletion: effects on ability to activate muscle phosphorylase

1986 ◽  
Vol 60 (5) ◽  
pp. 1518-1523 ◽  
Author(s):  
S. H. Constable ◽  
R. J. Favier ◽  
J. O. Holloszy
Keyword(s):  
Muscle Contraction ◽  
Muscle Glycogen ◽  
Contractile Activity ◽  
Strenuous Exercise ◽  
Glycogen Depletion ◽  
Significant Difference ◽  
Muscle Phosphorylase ◽  
Glycogen Repletion ◽  
Stimulation Of

Phosphorylase activation reverses during prolonged contractile activity. Our first experiment was designed to determine whether this loss of ability to activate phosphorylase by stimulation of muscle contraction persists following exercise. Phosphorylase activation by stimulation of muscle contraction was markedly inhibited in rats 25 min after exhausting exercise. To evaluate the role of glycogen depletion, we accelerated glycogen utilization by nicotinic acid administration. A large difference in muscle glycogen depletion during exercise of the same duration did not influence the blunting of phosphorylase activation. Phosphorylase activation by stimulation of contraction was more severely inhibited following prolonged exercise than after a shorter bout of exercise under conditions that resulted in the same degree of glycogen depletion. A large difference in muscle glycogen repletion during 90 min of recovery was not associated with a significant difference in the ability of muscle stimulation to activate phosphorylase, which was still significantly blunted. Phosphorylase activation by epinephrine was also markedly inhibited in muscle 25 min after strenuous exercise but had recovered completely in glycogen-repleted muscle 90 min after exercise. These results provide evidence that an effect of exercise other than glycogen depletion is involved in causing the inhibition of phosphorylase activation; however, they do not rule out the possibility that glycogen depletion also plays a role in this process.

scholarly journals Muscle Glycogenolysis and Resynthesis in Response to a Half Ironman Triathlon: A Case Study

2006 ◽  
Vol 1 (4) ◽  
pp. 408-413 ◽  
Author(s):  
Trevor L. Gillum ◽  
Charles L. Dumke ◽  
Brent C. Ruby
Keyword(s):  
Body Weight ◽  
Energy Expenditure ◽  
Muscle Glycogen ◽  
Vastus Lateralis ◽  
High Rate ◽  
Whole Body ◽  
Glycogen Depletion ◽  
Glycogen Resynthesis ◽  
Wet Weight ◽  
Ironman Triathlon

Purpose:To describe the degrees of muscle-glycogen depletion and resynthesis in response to a half Ironman triathlon.Methods:One male subject (38 years of age) completed the Grand Columbian half Ironman triathlon (1.9-km swim, 90-km bike, 21.1-km run, Coulee City, Wash). Three muscle biopsies were obtained from his right vastus lateralis (prerace, immediately postrace, and 4 hours postrace). Prerace and postrace body weight were recorded, in addition to macronutrient consumption before, during, and after the race. Energy expenditure and whole-body substrate oxidation were estimated from linear regression established from laboratory trials (watts and run pace relative to VO2 and VCO2).Results:Body weight decreased 3.8 kg from prerace to postrace. Estimated CHO energy expenditure was 10,003 kJ for the bike segment and 5759 kJ for the run segment of the race. The athlete consumed 308 g of exogenous CHO (liquid and gel; 1.21 g CHO/min) during the race. Muscle glycogen decreased from 227.1 prerace to 38.6 mmol · kg wet weight−1 · h−1 postrace. During the 4 hours postrace, the athlete consumed a mixed diet (471 g CHO, 15 g fat, 64 g protein), which included liquid CHO sources and a meal. The calculated rate of muscle-glycogen resynthesis was 4.1 mmol · kg wet weight−1 · h−1.Conclusion:Completing a half Ironman triathlon depends on a high rate of muscle glycogenolysis, which demonstrates the importance of exogenous carbohydrate intake during the race. In addition, rates of muscle-glycogen resynthesis might be dampened by the eccentric damage resulting from the run portion of the race.

scholarly journals 14–3-3 protein regulation of excitation–contraction coupling

2021 ◽  
Author(s):  
Walter C. Thompson ◽  
Paul H. Goldspink
Keyword(s):  
Protein Interactions ◽  
Protein Function ◽  
Force Generation ◽  
Client Protein ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
Cellular Processes ◽  
Disease States ◽  
Growing Body ◽  
Client Proteins

Abstract 14–3-3 proteins (14–3-3 s) are a family of highly conserved proteins that regulate many cellular processes in eukaryotes by interacting with a diverse array of client proteins. The 14–3-3 proteins have been implicated in several disease states and previous reviews have condensed the literature with respect to their structure, function, and the regulation of different cellular processes. This review focuses on the growing body of literature exploring the important role 14–3-3 proteins appear to play in regulating the biochemical and biophysical events associated with excitation–contraction coupling (ECC) in muscle. It presents both a timely and unique analysis that seeks to unite studies emphasizing the identification and diversity of 14–3-3 protein function and client protein interactions, as modulators of muscle contraction. It also highlights ideas within these two well-established but intersecting fields that support further investigation with respect to the mechanistic actions of 14–3-3 proteins in the modulation of force generation in muscle.

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