Adenosine exerts a glycogen-sparing action in contracting rat skeletal muscle

1997 ◽  
Vol 272 (5) ◽  
pp. E762-E768 ◽  
Author(s):  
L. Vergauwen ◽  
E. A. Richter ◽  
P. Hespel
Keyword(s):  
Skeletal Muscle ◽  
Glycogen Synthase ◽  
Fiber Type ◽  
Fiber Types ◽  
Adrenergic Stimulation ◽  
Receptor Antagonism ◽  
Glycogen Synthase Activity ◽  
Glycogen Sparing ◽  
Glycogen Breakdown

The role of adenosine in regulating glycogen breakdown during electrically induced muscle contractions was investigated in isolated rat hindquarters perfused with a standard medium either lacking or containing 100 microU/ml insulin and/or 1.67 nM isoprenaline. Nonselective A1/A2-adenosine receptor antagonism via caffeine enhanced (P < 0.05) glycogen breakdown in contracting fast-oxidative (FO) fibers by 40%, provided they were exposed to both insulin and isoprenaline. Combined A1/A2-receptor antagonism by 8-cyclopentyl-1,3-dipropylxanthine (CPDPX) plus 3,7-dimethyl-1-proparglyxanthine (DMPX) fully reproduced (P < 0.05) this stimulatory effect. Furthermore, CPDPX plus DMPX also enhanced (P < 0.05) glycogenolysis during contractions in soleus but not in white gastrocnemius muscle. In contrast, CPDPX or DMPX alone did not affect glycogenolysis in either fiber type. Muscle adenosine 3',5'-cyclic monophosphate concentration during contractions was increased (P < 0.05) by CPDPX plus DMPX in both fiber types, whereas glycogen synthase fractional activity was depressed (P < 0.05). Phosphorylase activity was not changed by CPDPX plus DMPX. It is concluded that adenosine exerts a glycogen-sparing action in oxidative skeletal muscle exposed to both insulin and beta-adrenergic stimulation during contraction, presumably via stimulation of glycogen synthase activity.

Insulin regulation of skeletal muscle glycogen metabolism

1980 ◽  
Vol 239 (1) ◽  
pp. E69-E74 ◽  
Author(s):  
J. L. Chiasson ◽  
M. R. Dietz ◽  
H. Shikama ◽  
M. Wootten ◽  
J. H. Exton
Keyword(s):  
Skeletal Muscle ◽  
Activity Ratio ◽  
Glycogen Synthase ◽  
Glycogen Metabolism ◽  
Effective Concentration ◽  
Threefold Increase ◽  
Glucose Clearance ◽  
Maximal Activation ◽  
Glycogen Synthase Activity

Using the perfused rat hindlimb preparation, the role of insulin in the regulation of glycogen metabolism in voluntary skeletal muscle has been characterized. A maximally effective concentration of insulin (1 mU/ml) caused a threefold increase in glucose clearance by 5 min. However, the -glucose-6-P/+glucose-6-P activity ratio of glycogen synthase was not significantly increased before 20 min. Insulin concentrations as low as 0.1 mU/ml significantly modified the glycogen synthase activity ratio and the half-maximal activation constant (A0.5) for glucose-6-P at 30 min, but had no effect on tissue cAMP. These changes were not dependent on the presence of glucose and were not modified by fasting. These results indicate that high physiological concentrations of insulin activate glycogen synthase in voluntary skeletal muscle and that this effect is independent of changes in glucose uptake or tissue cyclic AMP.

scholarly journals Super-relaxed state of myosin in human skeletal muscle is fiber-type dependent

2020 ◽  
Author(s):  
Lien A. Phung ◽  
Aurora D. Foster ◽  
Mark S. Miller ◽  
Dawn A. Lowe ◽  
David D. Thomas
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Epifluorescence Microscopy ◽  
Model Organisms ◽  
Muscle Physiology ◽  
Fiber Types ◽  
Mhc I

AbstractThe myosin super-relaxed state (SRX) in skeletal muscle is hypothesized to play an important role in regulating muscle contractility and thermogenesis in humans, but has only been examined in model organisms. Here we report the first human skeletal muscle SRX measurements, using quantitative epifluorescence microscopy of fluorescent 2’/3’-O-(N-methylanthraniloyl) ATP (mantATP) single-nucleotide turnover. Myosin heavy chain (MHC) isoform expression was determined using gel electrophoresis for each permeabilized vastus lateralis fiber, to allow for novel comparisons of SRX between fiber-types. We find that the fraction of myosin in SRX is less in MHC IIA fibers than in MHC I and IIAX fibers (p = 0.008). ATP turnover of SRX is faster in MHC IIAX fibers compared to MHC I and IIA fibers (p = 0.001). We conclude that SRX biochemistry is measurable in human skeletal muscle, and our data indicate that SRX depends on fiber type as classified by MHC isoform. Extension from this preliminary work would provide further understanding regarding the role of SRX in human muscle physiology.

Transgenic models – a scientific tool to understand exercise-induced metabolism: the regulatory role of AMPK (5′-AMP-activated protein kinase) in glucose transport and glycogen synthase activity in skeletal muscle

2003 ◽  
Vol 31 (6) ◽  
pp. 1290-1294 ◽  
Author(s):  
J.F.P. Wojtaszewski ◽  
J.N. Nielsen ◽  
S.B. Jørgensen ◽  
C. Frøsig ◽  
J.B. Birk ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Glucose Transport ◽  
Glycogen Synthase ◽  
Muscle Metabolism ◽  
Regulatory Role ◽  
Amp Activated Protein Kinase ◽  
Glycogen Synthase Activity

The AMPK (5´AMP-activated protein kinase) is becoming recognized as a critical regulator of energy metabolism. However, many of these effects in muscle metabolism have been ascribed to AMPK based on the use of the unspecific activator AICAR (5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside). Using mouse models in which AMPK activity has been specifically blocked (kinase dead) or knocked out we and others have been able to conduct studies gaining more conclusive data on the role of AMPK in muscle metabolism. In this mini-review focus is on AMPK and its regulatory role for glucose transport and GS (glycogen synthase) activity in skeletal muscle, indicating that AMPK is a GS kinase in vivo which might influence GS activity during exercise and that AMPK is involved in AICAR/hypoxia-induced glucose transport but not or only partially in contraction-stimulated glucose transport.

Role of glucocorticoid in the regulation of glycogen metabolism in skeletal muscle

1991 ◽  
Vol 260 (6) ◽  
pp. E927-E932 ◽  
Author(s):  
L. Coderre ◽  
A. K. Srivastava ◽  
J. L. Chiasson
Keyword(s):  
Skeletal Muscle ◽  
Muscle Contraction ◽  
Glycogen Phosphorylase ◽  
Glycogen Content ◽  
Glycogen Synthase ◽  
Glycogen Metabolism ◽  
Activity Ratios ◽  
Resting Muscle ◽  
Glycogen Breakdown

With the use of the hindlimb perfusion technique, the effect of glucocorticoid on the regulation of glycogen metabolism was studied in rat skeletal muscle. Rats were adrenalectomized (ADX) or sham operated (controls) 14 days before the study. The ADX animals were treated with either saline or corticosterone, and the hindlimbs were perfused at rest or during muscle contraction with saline or epinephrine (10(-7) M). In the resting state, the glycogen content was 33.0 +/- 1.9 mumol/g in the controls, and the activity ratios of glycogen phosphorylase (GPase) and glycogen synthase (GSase) were 0.27 +/- 0.03 and 0.15 +/- 0.02, respectively. Epinephrine treatment increased GPase activity (0.78 +/- 0.03) and decreased GSase activity (0.05 +/- 0.01), which resulted in decreased glycogen content (25.7 +/- 0.9 mumol/g; P less than 0.01). Adrenalectomy induced a 35% reduction in glycogen content but had no effect on the activities of basal enzymes. Under these conditions, however, epinephrine had no effect on GPase activity, had a diminished effect on GSase activity (0.11 +/- 0.01), and did not induce further glycogen breakdown. Corticosterone replacement normalized muscle glycogen content in ADX rats as well as the response of the enzymes to epinephrine. Muscle contraction resulted in a decrease in glycogen content (8.9 +/- 1.3 mumol/g) and in GPase activity (0.14 +/- 0.02) and an increase in GSase activity (0.25 +/- 0.01); this was not affected by adrenalectomy nor by epinephrine. In conclusion, these data indicate that glucocorticoid is essential for the effects of epinephrine on GPase activation. on GSase inhibition, and consequently on glycogen breakdown in resting muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of glycogen synthase activity in cultured skeletal muscle cells from subjects with type II diabetes: role of chronic hyperinsulinemia and hyperglycemia

Diabetes ◽  
1997 ◽  
Vol 46 (6) ◽  
pp. 1017-1024 ◽  
Author(s):  
S. E. Nikoulina ◽  
T. P. Ciaraldi ◽  
L. Abrams-Carter ◽  
S. Mudaliar ◽  
K. S. Park ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Type Ii Diabetes ◽  
Glycogen Synthase ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Type Ii ◽  
Glycogen Synthase Activity

scholarly journals Super-relaxed state of myosin in human skeletal muscle is fiber-type dependent

2020 ◽  
Vol 319 (6) ◽  
pp. C1158-C1162 ◽  
Author(s):  
Lien A. Phung ◽  
Aurora D. Foster ◽  
Mark S. Miller ◽  
Dawn A. Lowe ◽  
David D. Thomas
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Epifluorescence Microscopy ◽  
Model Organisms ◽  
Muscle Physiology ◽  
Fiber Types ◽  
Mhc I

The myosin super-relaxed state (SRX) in skeletal muscle is hypothesized to play an important role in regulating muscle contractility and thermogenesis in humans but has only been examined in model organisms. Here we report the first human skeletal muscle SRX measurements, using quantitative epifluorescence microscopy of fluorescent 2′/3′- O-( N-methylanthraniloyl) ATP (mantATP) single-nucleotide turnover. Myosin heavy chain (MHC) isoform expression was determined using gel electrophoresis for each permeabilized vastus lateralis fiber, to allow for novel comparisons of SRX between fiber types. We find that the fraction of myosin in SRX is less in MHC IIA fibers than in MHC I and IIAX fibers ( P = 0.008). ATP turnover of SRX is faster in MHC IIAX fibers compared with MHC I and IIA fibers ( P = 0.001). We conclude that SRX biochemistry is measurable in human skeletal muscle, and our data indicate that SRX depends on fiber type as classified by MHC isoform. Extension from this preliminary work would provide further understanding regarding the role of SRX in human muscle physiology.

Regulation of Glycogen Synthase Activity in Cultured Skeletal Muscle Cells From Subjects With Type II Diabetes: Role of Chronic Hyperinsulinemia and Hyperglycemia

Diabetes ◽  
1997 ◽  
Vol 46 (6) ◽  
pp. 1017-1024 ◽  
Author(s):  
S. E. Nikoulina ◽  
T. P. Ciaraldi ◽  
L. Abrams-Carter ◽  
S. Mudaliar ◽  
K. Park Soo ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Type Ii Diabetes ◽  
Glycogen Synthase ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Type Ii ◽  
Glycogen Synthase Activity

The KATP channel Kir6.2 subunit content is higher in glycolytic than oxidative skeletal muscle fibers

2011 ◽  
Vol 301 (4) ◽  
pp. R916-R925 ◽  
Author(s):  
Krystyna Banas ◽  
Charlene Clow ◽  
Bernard J. Jasmin ◽  
Jean-Marc Renaud
Keyword(s):  
Skeletal Muscle ◽  
Cross Sections ◽  
Fiber Type ◽  
Energy Levels ◽  
Muscle Fibers ◽  
Metabolic Stress ◽  
Oxidative Capacity ◽  
Fiber Types ◽  
Fiber Damage ◽  
The Individual

It has long been suggested that in skeletal muscle, the ATP-sensitive K+ channel (KATP) channel is important in protecting energy levels and that abolishing its activity causes fiber damage and severely impairs function. The responses to a lack of KATP channel activity vary between muscles and fibers, with the severity of the impairment being the highest in the most glycolytic muscle fibers. Furthermore, glycolytic muscle fibers are also expected to face metabolic stress more often than oxidative ones. The objective of this study was to determine whether the t-tubular KATP channel content differs between muscles and fiber types. KATP channel content was estimated using a semiquantitative immunofluorescence approach by staining cross sections from soleus, extensor digitorum longus (EDL), and flexor digitorum brevis (FDB) muscles with anti-Kir6.2 antibody. Fiber types were determined using serial cross sections stained with specific antimyosin I, IIA, IIB, and IIX antibodies. Changes in Kir6.2 content were compared with changes in CaV1.1 content, as this Ca2+ channel is responsible for triggering Ca2+ release from sarcoplasmic reticulum. The Kir6.2 content was the lowest in the oxidative soleus and the highest in the glycolytic EDL and FDB. At the individual fiber level, the Kir6.2 content within a muscle was in the order of type IIB > IIX > IIA ≥ I. Interestingly, the Kir6.2 content for a given fiber type was significantly different between soleus, EDL, and FDB, and highest in FDB. Correlations of relative fluorescence intensities from the Kir6.2 and CaV1.1 antibodies were significant for all three muscles. However, the variability in content between the three muscles or individual fibers was much greater for Kir6.2 than for CaV1.1. It is suggested that the t-tubular KATP channel content increases as the glycolytic capacity increases and as the oxidative capacity decreases and that the expression of KATP channels may be linked to how often muscles/fibers face metabolic stress.

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