Differential response of rat skeletal muscle glycogen metabolism to testosterone and estradiol

Although reports on sex steroids have implicated them as promoting protein synthesis and also providing extra strength to the skeletal muscle, it remains unclear whether sex steroids affect glycogen metabolism to provide energy for skeletal muscle functions, since glycogen metabolism is one of the pathways that provides energy for the skeletal muscle contraction and relaxation cycle. The purpose of the current study was to show that testosterone and estradiol act differentially on skeletal muscles from different regions, differentially with reference to glycogen metabolism. To study this hypothesis, healthy mature male Wistar rats (90-120 days of age, weighing about 180-200 g) were castrated (a bilateral orchidectomy was performed to test the significance of skeletal muscle glycogen metabolism in the absence of testosterone). One group of castrated rats was supplemented with testosterone (100 µg/100 g body weight, i.m., for 30 days from day 31 postcastration onwards). To test whether estradiol has any effect on male skeletal muscle glycogen metabolism 17beta-estradiol (5 µg/100 g body weight, i.m., for 30 days from day 31 postcastration onwards) was administered to orchidectomized rats. To test whether these sex steroids have any differential effect on skeletal muscles from different regions, skeletal muscles from the temporal region (temporalis), muscle of mastication (masseter), forearm muscle (triceps and biceps), thigh muscle (vastus lateralis and gracilis), and calf muscle (gastrocnemius and soleus) were considered. Castration enhanced blood glucose levels and decreased glycogen stores in skeletal muscle from head, jaw, forearm, thigh, and leg regions. This was accompanied by diminished activity of glycogen synthetase and enhanced activity of muscle phosphorylase. Following testosterone supplementation to castrated rats, a normal pattern of all these parameters was maintained. Estradiol administration to castrated rats did not bring about any significant alteration in any of the parameters. The data obtained suggest a stimulatory effect of testosterone on skeletal muscle glycogenesis and an inhibitory effect on glycogenolysis. Estradiol did not play any significant role in the skeletal muscle glycogen metabolism of male rats.Key words: testosterone, estradiol, skeletal muscle, glycogen metabolism.

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Differential response of rat cardiac and skeletal muscle glycogen to glucocorticoids

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y82-086 ◽

1982 ◽

Vol 60 (5) ◽

pp. 634-637 ◽

Cited By ~ 4

Author(s):

James L. Poland ◽

Jerry W. Poland ◽

Richard N. Honey

Keyword(s):

Skeletal Muscle ◽

Muscle Glycogen ◽

Skeletal Muscles ◽

Vastus Lateralis ◽

Experimental Period ◽

Plasma Free Fatty Acid ◽

Liver Glycogen ◽

Skeletal Muscle Glycogen ◽

Exercise Induced ◽

Peak Value

Though glucocorticoids were previously implicated in the support of myocardial glycogen supercompensation after exercise, it was unclear why skeletal muscle glycogen did not simultaneously supercompensate since it was also exposed to the exercise-induced glucocorticoid increases. The current study shows that glucocorticoids differentially affect cardiac and skeletal muscle glycogen. Following dexamethasone administration (400 μg i.p.) myocardial glycogen peaked at 6 h while glycogen in the soleus, red vastus lateralis, and white vastus lateralis increased more slowly and reached the highest values 17 h postinjection. Concurrently, blood glucose, insulin, and glucagon remained at control levels. Liver glycogen increased within 2 h and continued to rise with a peak value at 17 h. Plasma free fatty acid (FFA) levels increased and remained high throughout the 26-h experimental period. High FFA levels inhibit glycogenolysis and thus could be partially responsible for glucocorticoid-induced glycogen increases. It is postulated that glycogen supercompensation does not readily occur in skeletal muscles after exercise because of the brevity of the corticosterone and FFA increases and the slowness of the skeletal muscle glycogen response to glucocorticoids.

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Glikogen Otot Rangka Ayam Broiler (Gallus gallus) setelah Pemberian Teh Kombucha dalam Air Minum

Bioma Berkala Ilmiah Biologi ◽

10.14710/bioma.20.2.78-85 ◽

2019 ◽

Vol 20 (2) ◽

pp. 78

Author(s):

Nasrul Fathoni ◽

M Anwar Djaelani ◽

Sri Isdadiyanto

Keyword(s):

Skeletal Muscle ◽

Drinking Water ◽

Body Weight ◽

Green Tea ◽

Muscle Glycogen ◽

Broiler Chickens ◽

Gallus Gallus ◽

Feed Consumption ◽

Skeletal Muscle Glycogen ◽

Kombucha Tea

Kombucha tea beverage obtained by fermenting sweetened green tea for 12 days with Acetobacter xylinum and Saccharomyces which produce various kinds of organic acids, vitamins, and acts as a probiotic. The role of kombucha tea as a growth promoter is to that improve the metabolic process in the digestion of broiler chickens, so that nutrients can and fulfilled optimally for growth and development. The aim of this research was to analyze the sceletal muscle glycogen glycogen (Gallus gallus) after treat with kombucha tea in drinking water. Kombucha tea used is the result of fermentation of green tea for 12 days. This research used DOC chickens (Day Old Chicken) as much as 20 randomly divided into 4 treatments with concentration ie 0%, 10%, 20%, and 40% kombucha tea in drinking water for 32 days. The variables measured were skeletal muscle glycogen levels, body weight, feed consumption and drink consumption. The data obtained were analyzed using ANOVA followed by Duncan Test with 95% confidence level using SPSS 17.0 software. The results of this study showed that kombucha tea on skeletal muscle glycogen and feed consumption showed no significant difference, while on body weight and drink consumption showed significantly different results. Based on the results of the study, it can be concluded that giving kombucha tea in drinking water to a concentration of 40% has not been able to affect the skeletal muscle glycogen in broiler chickens. Key words: Kombucha tea, broiler chicken, glycogen skeletal muscle

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Human Skeletal Muscle Glycogen Branching Enzyme Activities with Exercise and Training

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y74-016 ◽

1974 ◽

Vol 52 (1) ◽

pp. 119-122 ◽

Cited By ~ 5

Author(s):

A. W. Taylor ◽

J. Stothart ◽

M. A. Booth ◽

R. Thayer ◽

S. Rao

Keyword(s):

Skeletal Muscle ◽

Muscle Glycogen ◽

Enzyme Activities ◽

Vastus Lateralis ◽

Submaximal Exercise ◽

Relative Fitness ◽

Vastus Lateralis Muscle ◽

Branching Enzyme ◽

Skeletal Muscle Glycogen ◽

Glycogen Branching Enzyme

Sixteen healthy male subjects classified as sedentary (8) or active (8), exercised to exhaustion on a bicycle ergometer at a load requiring 70% of their maximal aerobic capacity. Biopsy samples of the vastus lateralis muscle were taken at rest and at the time of fatigue. A 12 week training program increased skeletal muscle glycogen content and branching enzyme activities twofold. The exhaustive submaximal exercise reduced the glycogen levels of the trained group to values similar to the fatigue levels of the non-trained subjects. Skeletal muscle glycogen branching enzyme activities decreased with submaximal exercise to fatigue in all groups. Maximal exercise to fatigue resulted in small increases in the activities of the enzyme. The results of the present study and a previous study (Taylor et al. 1972. Can. J. Physiol. Pharmacol. 50, 411–415) indicate that the activities of the glycogen synthesizing enzymes are highly correlated with the skeletal muscle resting glycogen concentration and the relative fitness of the subjects.

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Subcellular localization-dependent decrements in skeletal muscle glycogen and mitochondria content following short-term disuse in young and old men

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00324.2010 ◽

2010 ◽

Vol 299 (6) ◽

pp. E1053-E1060 ◽

Cited By ~ 28

Author(s):

Joachim Nielsen ◽

Charlotte Suetta ◽

Lars G. Hvid ◽

Henrik D. Schrøder ◽

Per Aagaard ◽

...

Keyword(s):

Skeletal Muscle ◽

Muscle Glycogen ◽

Vastus Lateralis ◽

Age Groups ◽

Quadriceps Muscle ◽

Fiber Types ◽

Short Term ◽

Skeletal Muscle Glycogen ◽

Before And After ◽

Old Men

Previous studies have shown that skeletal muscle glycogen and mitochondria are distributed in distinct subcellular localizations, but the role and regulation of these subcellular localizations are unclear. In the present study, we used transmission electron microscopy to investigate the effect of disuse and aging on human skeletal muscle glycogen and mitochondria content in subsarcolemmal (SS), intermyofibrillar (IMF), and intramyofibrillar (intra) localizations. Five young (∼23 yr) and five old (∼66 yr) recreationally active men had their quadriceps muscle immobilized for 2 wk by whole leg casting. Biopsies were obtained from m. vastus lateralis before and after the immobilization period. Immobilization induced a decrement of intra glycogen content by 54% ( P < 0.001) in both age groups and in two ultrastructurally distinct fiber types, whereas the content of IMF and SS glycogen remained unchanged. A localization-dependent decrease ( P = 0.03) in mitochondria content following immobilization was found in both age groups, where SS mitochondria decreased by 33% ( P = 0.02), superficial IMF mitochondria decreased by 20% ( P = 0.05), and central IMF mitochondria remained unchanged. In conclusion, our findings demonstrate a localization-dependent adaptation to immobilization in glycogen and mitochondria content of skeletal muscles of both young and old individuals. Specifically, this suggests that short-term disuse preferentially affects glycogen particles located inside the myofibrils and that mitochondria volume plasticity can be dependent on the distance to the fiber border.

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Determinants of insulin-stimulated skeletal muscle glycogen metabolism in man

European Journal of Clinical Investigation ◽

10.1111/j.1365-2362.1995.tb01988.x ◽

1995 ◽

Vol 25 (9) ◽

pp. 693-698 ◽

Cited By ~ 7

Author(s):

C. SCHALIN-JÄNTTI ◽

E. LAURILA ◽

M. LÖFMAN ◽

L. C. GROOP

Keyword(s):

Skeletal Muscle ◽

Muscle Glycogen ◽

Glycogen Metabolism ◽

Skeletal Muscle Glycogen

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Mutations of the serine phosphorylated in the protein phosphatase-1-binding motif in the skeletal muscle glycogen-targeting subunit

Biochemical Journal ◽

10.1042/bj3460077 ◽

2000 ◽

Vol 346 (1) ◽

pp. 77-82 ◽

Cited By ~ 9

Author(s):

Jun LIU ◽

Jun WU ◽

Carey OLIVER ◽

Shirish SHENOLIKAR ◽

David L. BRAUTIGAN

Keyword(s):

Skeletal Muscle ◽

Muscle Glycogen ◽

Protein Phosphatase ◽

Glycogen Metabolism ◽

Binding Activity ◽

Hormonal Control ◽

Protein Phosphatase 1 ◽

Binding Motif ◽

Unique Contribution ◽

Skeletal Muscle Glycogen

Cellular functions of protein phosphatase-1 (PP1) are determined by regulatory subunits that contain the consensus PP1-binding motif, RVXF. This motif was first identified as the site of phosphorylation by cAMP-dependent protein kinase (PKA) in a skeletal muscle glycogen-targeting subunit (GM). We reported previously that a recombinant fusion protein of glutathione S-transferase (GST) and the N-terminal domain of GM [GST-GM-(1-240)] bound PP1 in a pull down assay, and phosphorylation by PKA prevented PP1 binding. Here we report that substitution of either Ala or Val for Ser-67 in the RVS67F motif in GST-GM-(1-240) essentially eliminated PP1 binding. This was unexpected because other glycogen-targeting subunits have a Val residue at the position corresponding to Ser-67. In contrast, a mutation of Ser-67 to Thr (S67T) in GST-GM(1-240) gave a protein that bound PP1 the same as wild type and was unaffected by PKA phosphorylation. Full length GM tagged with the epitope sequence DYKDDDDK (FLAG) expressed in COS7 cells bound PP1 that was recovered by co-immunoprecipitation, but this association was prevented by treatment of the cells with forskolin. By comparison, PP1 binding with FLAG-GM(S67T) was not disrupted by forskolin treatment. Neither FLAG-GM(S67A) nor FLAG-GM(S67V) formed stable complexes with PP1 in COS7 cells. These results emphasise the unique contribution of Ser-67 in PP1 binding to GM. The constitutive PP1-binding activity shown by GM(S67T) opens the way for studying the role of GM multisite phosphorylation in hormonal control of glycogen metabolism.

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