scholarly journals NMR of glycogen in exercise

1999 ◽  
Vol 58 (4) ◽  
pp. 851-859 ◽  
Author(s):  
Thomas B. Price ◽  
Douglas L. Rothman ◽  
Robert G. Shulman
Keyword(s):  
Time Resolution ◽  
Muscle Glycogen ◽  
Time Course ◽  
Glycogen Synthesis ◽  
Liver Glycogen ◽  
Invasive Technique ◽  
Human Populations ◽  
Glycogen Depletion ◽  
Non Invasive ◽  
C Nmr

Natural-abundance 13CNMR spectroscopy is a non-invasive technique that enables in vivo assessments of muscle and/or liver glycogen concentrations. Over the last several years, 13C NMR has been developed and used to obtain information about human glycogen metabolism with diet and exercise. Since NMR is non-invasive, more data points are available over a specified time course, dramatically improving the time resolution. This improved time resolution has enabled the documentation of subtleties of muscle glycogen re-synthesis following severe glycogen depletion that were not previously observed. Muscle and liver glycogen concentrations have been tracked in several different human populations under conditions that include: (1) muscle glycogen recovery from intense localized exercise with normal insulin and with insulin suppressed; (2) muscle glycogen recovery in an insulin-resistant population; (3) muscle glycogen depletion during prolonged low-intensity exercise; (4) effect of a mixed meal on postprandial muscle and liver glycogen synthesis. The present review focuses on basic 13C NMR and gives results from selected studies.

Preferential resynthesis of muscle glycogen in fasting rats after exhausting exercise

1980 ◽  
Vol 238 (5) ◽  
pp. R328-R332 ◽  
Author(s):  
R. D. Fell ◽  
J. A. McLane ◽  
W. W. Winder ◽  
J. O. Holloszy
Keyword(s):  
Muscle Glycogen ◽  
Glycogen Synthesis ◽  
Liver Glycogen ◽  
Glycogen Depletion ◽  
Glycogen Accumulation ◽  
Exhausting Exercise ◽  
Hindlimb Muscles ◽  
Carbohydrate Starvation ◽  
Fat Feeding ◽  
Very High

Despite carbohydrate starvation (fasting or fat feeding) considerable glycogen accumulation, ranging from 20 to 30 mumol glucose/g, occurred in hindlimb muscles of rats following exhausting exercise that caused severe muscle and liver glycogen depletion and hypoglycemia. The largest increase in muscle glycogen occurred during the first 3 h after exercise when plasma levels of glucagon and epinephrine were very high and insulin concentration was low. The concentrations of glycogen attained in different hindlimb muscles in the fasting and fat-fed animals were between 50 and 100% of the values found in rats fed carbohydrate after the exhausting exercise. In rats fed carbohydrate following exercise, liver glycogen accumulation greatly exceeds muscle glycogen accumulation. A remarkable difference in the response of liver glycogen was seen in the carbohydrate starved rats. In contrast to the rapid increase in muscle glycogen, liver glycogen was still essentially completely depleted in the fasting and fat-fed rats 24 h after exercise. This indicates that the glucose made available via gluconeogenesis was preferentialy channeled away from liver glycogen synthesis into muscle glycogen.

Metabolic and hormonal changes following endotoxin administration to diabetic rats

1982 ◽  
Vol 243 (1) ◽  
pp. R77-R81
Author(s):  
D. L. Kelleher ◽  
B. C. Fong ◽  
G. J. Bagby ◽  
J. J. Spitzer
Keyword(s):  
Plasma Glucose ◽  
Time Course ◽  
Glycogen Content ◽  
Metabolic Response ◽  
Insulin Response ◽  
Liver Glycogen ◽  
Diabetic Rats ◽  
Hormonal Changes ◽  
Glycogen Depletion ◽  
Endotoxin Administration

The aim of these investigations was to study the time course and cause of the altered metabolic response of diabetic rats to endotoxin administration. Escherichia coli endotoxin was administered to streptozotocin-diabetic and control normoglycemic rats. At 1, 2, 5, 8, and 24 h following endotoxin, animals were decapitated. Plasma samples were analyzed for glucose, lactate, insulin, glucagon, and corticosteroids. In addition, tissue glycogen content of liver and skeletal muscle was determined. Endotoxin caused an elevation of plasma glucose in both diabetic and normoglycemic rats by 1 h postinjection. The elevation was prolonged in diabetic rats for 8 h but lasted only 2 h in nondiabetic rats. Both endotoxin-treated groups demonstrated hyperlactacidemia following endotoxin. Endotoxin led to liver glycogen depletion in both diabetic and normoglycemic rats, whereas muscle glycogen content was only slightly affected. Plasma glucagon and corticosteroids rose immediately and remained elevated in both endotoxin-treated groups. A significant insulin response to rising plasma glucose was observed in nondiabetic but not in diabetic rats following endotoxin. These results suggest that the exaggerated and prolonged hyperglycemia observed in diabetic endotoxin-treated rats is due to hypersecretion of glucose-mobilizing hormones and elevated gluconeogenesis, unmatched by an adequate secretion of insulin to promote glucose uptake and utilization.

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.

Muscle glycogen recovery after exercise during glucose and fructose intake monitored by13C-NMR

1996 ◽  
Vol 81 (4) ◽  
pp. 1495-1500 ◽  
Author(s):  
Adrianus J. Van Den Bergh ◽  
Sibrand Houtman ◽  
Arend Heerschap ◽  
Nancy J. Rehrer ◽  
Hendrikus J. Van Den Boogert ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Muscle Glycogen ◽  
Glycogen Content ◽  
Vastus Lateralis ◽  
Glycogen Depletion ◽  
Glycogen Concentration ◽  
Fructose Intake ◽  
Glycogen Stores ◽  
Male Subjects ◽  
C Nmr

Van Den Bergh, Adrianus J., Sibrand Houtman, Arend Heerschap, Nancy J. Rehrer, Hendrikus J. Van Den Boogert, Berend Oeseburg, and Maria T. E. Hopman. Muscle glycogen recovery after exercise during glucose and fructose intake monitored by13C-NMR. J. Appl. Physiol. 81(4): 1495–1500, 1996.—The purpose of this study was to examine muscle glycogen recovery with glucose feeding (GF) compared with fructose feeding (FF) during the first 8 h after partial glycogen depletion by using13C-nuclear magnetic resonance (NMR) on a clinical 1.5-T NMR system. After measurement of the glycogen concentration of the vastus lateralis (VL) muscle in seven male subjects, glycogen stores of the VL were depleted by bicycle exercise. During 8 h after completion of exercise, subjects were orally given either GF or FF while the glycogen content of the VL was monitored by13C-NMR spectroscopy every second hour. The muscular glycogen concentration was expressed as a percentage of the glycogen concentration measured before exercise. The glycogen recovery rate during GF (4.2 ± 0.2%/h) was significantly higher ( P < 0.05) compared with values during FF (2.2 ± 0.3%/h). This study shows that 1) muscle glycogen levels are perceptible by 13C-NMR spectroscopy at 1.5 T and 2) the glycogen restoration rate is higher after GF compared with after FF.

Tissue Glycogen Synthesis in Adrenalectomized Rats Fed Glycine-Containing Diets and Given Hydrocortisone

1958 ◽  
Vol 195 (3) ◽  
pp. 643-644 ◽  
Author(s):  
W. R. Todd ◽  
Marilouise Allen
Keyword(s):  
Body Weight ◽  
Muscle Glycogen ◽  
Control Diet ◽  
Glycogen Synthesis ◽  
Liver Glycogen ◽  
Adrenal Hormone ◽  
Adrenalectomized Rats

Adrenalectomized rats were fed diets with or without added glycine for 36 hours; 4 hours later they were made to swim in 14°C water (the stress). Liver and muscle glycogen determinations at this time showed the levels to be essentially the same in the two groups of rats. When 1 mg of hydrocortisone per 100 gm body weight was given twice a day for 2 days prior to the stress, the glycine-fed animals showed nearly twice as much liver glycogen as the animals prefed the control diet. Muscle glycogen concentrations were not different. Adrenal hormone, glycine and stress are required to demonstrate the ‘protein effect’ of glycine. It now appears, however, that increased adrenal hormone is not a prerequisite.

Postexercise muscle and liver glycogen metabolism in male and female rats

1987 ◽  
Vol 62 (3) ◽  
pp. 1250-1254 ◽  
Author(s):  
P. A. Ivey ◽  
G. A. Gaesser
Keyword(s):  
Sex Difference ◽  
Muscle Glycogen ◽  
Exercise Bout ◽  
Glycogen Metabolism ◽  
Liver Glycogen ◽  
Female Rats ◽  
Glycogen Depletion ◽  
Male And Female ◽  
Glycogen Repletion ◽  
Fast Twitch

Male and female Wistar rats were run for 5 min at 1.7 mph at a 17% grade to determine whether a sex difference exists in the rate of glycogen resynthesis during recovery in fast-twitch red muscle, fast-twitch white muscle, and liver. Rats were killed at one of three time points: immediately after the exercise bout, and at 1 or 4 h later. Males had significantly higher resting muscle glycogen levels (P less than 0.05). Exercise resulted in significant glycogen depletion in both sexes (P less than 0.01). Males utilized approximately 50% more glycogen during the exercise bout than females (P less than 0.05). During the food-restricted 4-h recovery period, muscle glycogen was repleted significantly during the 1st h (P less than 0.05). Liver glycogen was not depleted as a result of the exercise bout, but fell during the first h of recovery (P less than 0.05) and remained low during the subsequent 3 h. The greater glycogen utilization in red and white fast-twitch muscle during exercise by males could represent a true sex difference but could also be attributable in part to the males having performed more work as a result of 20% greater body mass. We conclude that no sex difference was observed in the rates of muscle glycogen repletion after exercise or in liver glycogen metabolism during and after exercise, and rapid postexercise muscle glycogen repletion occurred at a time of accelerated liver glycogen depletion.

Circadian rhythm in sensitivity of glucose metabolism to insulin in rat soleus muscle

1988 ◽  
Vol 255 (1) ◽  
pp. E41-E45 ◽  
Author(s):  
B. Leighton ◽  
J. M. Kowalchuk ◽  
R. A. Challiss ◽  
E. A. Newsholme
Keyword(s):  
Skeletal Muscle ◽  
Glucose Metabolism ◽  
Muscle Glycogen ◽  
Blood Glucose Concentration ◽  
Glycogen Synthesis ◽  
Liver Glycogen ◽  
Hepatic Glycogen ◽  
Feeding Period ◽  
Rat Soleus Muscle ◽  
Animal House

This study determined whether the sensitivity of glucose metabolism to insulin in skeletal muscle varies during a 24-h period. Soleus muscles were isolated from ad libitum-fed rats killed at 0900, 1600, 2100, and 0300. The animal house was illuminated between 0800 and 2000. The sensitivities of glycolysis (which is an excellent index of glucose transport) and glycogen synthesis to insulin were greatest in muscles isolated at 0900 and 2100. Marked decreases in sensitivities of both processes to insulin were observed in muscles isolated at 0300 and 1600, which are times halfway through the feeding and postabsorptive periods, respectively. Hence, this study demonstrates circadian changes in the sensitivity of glucose utilization by skeletal muscle to insulin, which may be important in control of blood glucose concentration. Glycogen levels in skeletal muscles were highest at 0300 and lowest at 2100; hepatic glycogen content reached a peak at 0900, and the lowest content was measured at 2100. The liver glycogen level was increased by only 15% midway into the feeding period (i.e., 0300). This suggests that muscle glycogen may act as a temporary store of glucose residues during the feeding period; it stores glycogen in the first half of the feeding period but during the second half some muscle glycogen is converted to lactate, which acts as a precursor for hepatic gluconeogenesis.

Time course of insulin action on tissue-specific intracellular glucose metabolism in normal rats

1998 ◽  
Vol 274 (4) ◽  
pp. E642-E650 ◽  
Author(s):  
Sietse J. Koopmans ◽  
Lawrence Mandarino ◽  
Ralph A. Defronzo
Keyword(s):  
Insulin Action ◽  
Time Course ◽  
Hepatic Glucose Production ◽  
Glycogen Synthesis ◽  
Glucose Production ◽  
Liver Glycogen ◽  
Whole Body ◽  
Glucose Disposal ◽  
Muscle Glycogen Synthesis ◽  
The Face

We investigated the time course of insulin action in conscious rats exposed to constant physiological hyperinsulinemia (∼100 mU/l) while maintaining euglycemia (∼100 mg/dl) for 0, 0.5, 2, 4, 8, or 12 h. [3-3H]glucose was infused to quantitate whole body glucose disposal (rate of disappearance, Rd), glycolysis (generation of3H2O in plasma), hepatic glucose production (HGP), and skeletal muscle and liver glycogen synthesis ([3-3H]glucose incorporation into glycogen and time-dependent change in tissue glycogen concentration). The basal Rd, which equals HGP, was 6.0 ± 0.3 mg ⋅ kg−1 ⋅ min−1. With increased duration of hyperinsulinemia from 0 to 0.5 to 2 to 4 h, Rd increased from 6.0 ± 0.3 to 21.0 ± 1.1 to 24.1 ± 1.5 to 26.6 ± 0.6 mg ⋅ kg−1 ⋅ min−1( P < 0.05 for 2 and 4 h vs. 0.5 h). During the first 2 h the increase in Rd was explained by parallel increases in glycolysis and glycogen synthesis. From 2 to 4 h the further increase in Rd was entirely due to an increase in glycolysis without change in glycogen synthesis. From 4 to 8 to 12 h of hyperinsulinemia, Rd decreased by 19% from 26.6 ± 0.6 to 24.1 ± 1.1 to 21.6 ± 1.8 mg ⋅ kg−1 ⋅ min−1( P < 0.05 for 8 h vs. 4 h and 12 h vs. 8 h). The progressive decline in Rd, in the face of constant hyperinsulinemia, occurred despite a slight increase (8–14%) in glycolysis and was completely explained by a marked decrease (64%) in muscle glycogen synthesis. In contrast, liver glycogen synthesis increased fourfold, indicating an independent regulation of muscle and liver glycogen synthesis by long-term hyperinsulinemia. In the liver, during the entire 12-h period of insulin stimulation, the contribution of the direct (from glucose) and the indirect (from C-3 fragments) pathways to net glycogen formation remained constant at 77 ± 5 and 23 ± 5%, respectively. HGP remained suppressed throughout the 12-h period of hyperinsulinemia.

Carbohydrate, Fluids and Electrolyte Requirements of the Soccer Player: A Stewiew

1994 ◽  
Vol 4 (3) ◽  
pp. 221-236 ◽  
Author(s):  
John A. Hawley ◽  
Steven C. Dennis ◽  
Timothy D. Noakes
Keyword(s):  
Body Weight ◽  
Muscle Glycogen ◽  
Soccer Player ◽  
Liver Glycogen ◽  
Soccer Players ◽  
Insufficient Evidence ◽  
Glycogen Depletion ◽  
Low Concentrations ◽  
Glycogen Stores ◽  
Glycogen Sparing

Soccer requires field players to exercise repetitively at high intensities for the duration of a game, which can result in marked muscle glycogen depletion and hypoglycemia. A soccer match places heavy demands on endogenous muscle and liver glycogen stores and fluid reserves, which must be rapidly replenished when players complete several matches within a brief period of time. Low concentrations of muscle glycogen have been reported in soccer players before a game, and daily carbohydrate (CHO) intakes are often insufficient to replenish muscle glycogen stores, CHO supplementation during soccer matches has been found to result in muscle glycogen sparing (39%), greater second-half running distances, and more goals being scored with less conceded, when compared to consumption of water. Thus, CHO supplementation has been recommended prior to, during, and after matches. In contrast, there is currently insufficient evidence to recommend without reservation the addition of electrolytes to a beverage for ingestion by players during a game resulting in sweat losses of < 4% of body weight.

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