Hyperthyroidism and cation pumps in human skeletal muscle

2005 ◽  
Vol 288 (6) ◽  
pp. E1265-E1269 ◽  
Author(s):  
Anne Lene Dalkjær Riis ◽  
Jens Otto Lunde Jørgensen ◽  
Niels Møller ◽  
Jørgen Weeke ◽  
Torben Clausen
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Vastus Lateralis ◽  
Vastus Lateralis Muscle ◽  
Healthy Controls ◽  
Thyroid Status ◽  
Before And After ◽  
Muscle Biopsies ◽  
Hyperthyroid Patients ◽  
Major Target

Skeletal muscle constitutes the major target organ for the thermogenic action of thyroid hormone. We examined the possible relation between energy expenditure (EE), thyroid status, and the contents of Ca2+-ATPase and Na+-K+-ATPasein human skeletal muscle. Eleven hyperthyroid patients with Graves' disease were studied before and after medical treatment with methimazole and compared with eight healthy subjects. Muscle biopsies were taken from the vastus lateralis muscle, and EE was determined by indirect calorimetry. Before treatment, the patients had two- to fivefold elevated total plasma T3 and 41% elevated EE compared with when euthyroidism had been achieved. In hyperthyroidism, the content of Ca2+-ATPase was increased: (mean ± SD) 6,555 ± 604 vs. 5,212 ± 1,580 pmol/g in euthyroidism ( P = 0.04) and 4,523 ± 1,311 pmol/g in healthy controls ( P = 0.0005). The content of Na+-K+-ATPase showed 89% increase in hyperthyroidism: 558 ± 101 vs. 296 ± 34 pmol/g ( P = 0.0001) in euthyroidism and 278 ± 52 pmol/g in healthy controls ( P < 0.0001). In euthyroidism, the contents of both cation pumps did not differ from those of healthy controls. The Ca2+-ATPase content was significantly correlated to plasma T3 and resting EE. This provides the first evidence that, in human skeletal muscle, the capacity for Ca2+ recycling and active Na+-K+ transport are correlated to EE and thyroid status.

Effects of 7 wk of endurance training on human skeletal muscle metabolism during submaximal exercise

2004 ◽  
Vol 97 (6) ◽  
pp. 2148-2153 ◽  
Author(s):  
Paul J. LeBlanc ◽  
Krista R. Howarth ◽  
Martin J. Gibala ◽  
George J. F. Heigenhauser
Keyword(s):  
Skeletal Muscle ◽  
Endurance Training ◽  
Glycogen Phosphorylase ◽  
Human Skeletal Muscle ◽  
Vastus Lateralis ◽  
Muscle Metabolism ◽  
Allosteric Modulators ◽  
Before And After ◽  
First Time ◽  
Muscle Biopsies

This is the first study to examine the effects of endurance training on the activation state of glycogen phosphorylase (Phos) and pyruvate dehydrogenase (PDH) in human skeletal muscle during exercise. We hypothesized that 7 wk of endurance training (Tr) would result in a posttransformationally regulated decrease in flux through Phos and an attenuated activation of PDH during exercise due to alterations in key allosteric modulators of these important enzymes. Eight healthy men (22 ± 1 yr) cycled to exhaustion at the same absolute workload (206 ± 5 W; ∼80% of initial maximal oxygen uptake) before and after Tr. Muscle biopsies (vastus lateralis) were obtained at rest and after 5 and 15 min of exercise. Fifteen minutes of exercise post-Tr resulted in an attenuated activation of PDH (pre-Tr: 3.75 ± 0.48 vs. post-Tr: 2.65 ± 0.38 mmol·min−1·kg wet wt−1), possibly due in part to lower pyruvate content (pre-Tr: 0.94 ± 0.14 vs. post-Tr: 0.46 ± 0.03 mmol/kg dry wt). The decreased pyruvate availability during exercise post-Tr may be due to a decreased muscle glycogenolytic rate (pre-Tr: 13.22 ± 1.01 vs. post-Tr: 7.36 ± 1.26 mmol·min−1·kg dry wt−1). Decreased glycogenolysis was likely mediated, in part, by posttransformational regulation of Phos, as evidenced by smaller net increases in calculated muscle free ADP (pre-Tr: 111 ± 16 vs. post-Tr: 84 ± 10 μmol/kg dry wt) and Pi (pre-Tr: 57.1 ± 7.9 vs. post-Tr: 28.6 ± 5.6 mmol/kg dry wt). We have demonstrated for the first time that several signals act to coordinately regulate Phos and PDH, and thus carbohydrate metabolism, in human skeletal muscle after 7 wk of endurance training.

scholarly journals Angiogenesis-related ultrastructural changes to capillaries in human skeletal muscle in response to endurance exercise

2015 ◽  
Vol 119 (10) ◽  
pp. 1118-1126 ◽  
Author(s):  
Oliver Baum ◽  
Jennifer Gübeli ◽  
Sebastian Frese ◽  
Eleonora Torchetti ◽  
Corinna Malik ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cross Sections ◽  
Human Skeletal Muscle ◽  
Vastus Lateralis ◽  
Capillary Density ◽  
Volume Density ◽  
Ultrastructural Changes ◽  
Vastus Lateralis Muscle ◽  
Before And After ◽  
Exercise Induced

The ultrastructure of capillaries in skeletal muscle was morphometrically assessed in vastus lateralis muscle (VL) biopsies taken before and after exercise from 22 participants of two training studies. In study 1 (8 wk of ergometer training), light microscopy revealed capillary-fiber (C/F) ratio (+27%) and capillary density (+16%) to be higher ( P ≤ 0.05) in postexercise biopsies than in preexercise biopsies from all 10 participants. In study 2 (6 mo of moderate running), C/F ratio and capillary density were increased (+23% and +20%; respectively, P ≤ 0.05) in VL biopsies from 6 angiogenesis responders (AR) after training, whereas 6 nonangiogenesis responders (NR) showed nonsignificant changes in these structural indicators (−4%/−4%, respectively). Forty capillary profiles per participant were evaluated by point and intersection counting on cross sections after transmission electron microscopy. In study 1, volume density (Vv) and mean arithmetic thickness (T) of endothelial cells (ECs; +19%/+17%, respectively) and pericytes (PCs; +20%/+21%, respectively) were higher ( P ≤ 0.05), whereas Vv and T of the pericapillary basement membrane (BM) were −23%/−22% lower ( P ≤ 0.05), respectively, in posttraining biopsies. In study 2, exercise-related differences between AR and NR-groups were found for Vv and T of PCs (AR, +26%/+22%, respectively, both P ≤ 0.05; NR, +1%/−3%, respectively, both P > 0.05) and BM (AR, −14%/−13%, respectively, both P ≤ 0.05; NR, −9%/−11%, respectively, P = 0.07/0.10). Vv and T of ECs were higher (AR, +16%/+18%, respectively; NR, +6% /+6%, respectively; all P ≤ 0.05) in both groups. The PC coverage was higher (+13%, P ≤ 0.05) in VL biopsies of individuals in the AR group but nonsignificantly altered (+3%, P > 0.05) in those of the NR group after training. Our study suggests that intensified PC mobilization and BM thinning are related to exercise-induced angiogenesis in human skeletal muscle, whereas training per se induces EC-thickening.

Bed rest reduces metabolic protein content and abolishes exercise-induced mRNA responses in human skeletal muscle

2011 ◽  
Vol 301 (4) ◽  
pp. E649-E658 ◽  
Author(s):  
Stine Ringholm ◽  
Rasmus S. Biensø ◽  
Kristian Kiilerich ◽  
Amelia Guadalupe-Grau ◽  
Niels Jacob Aachmann-Andersen ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Content ◽  
Human Skeletal Muscle ◽  
Citrate Synthase ◽  
Bed Rest ◽  
Sirtuin 1 ◽  
Vastus Lateralis Muscle ◽  
Before And After ◽  
Exercise Induced ◽  
Muscle Biopsies

The aim was to test the hypothesis that 7 days of bed rest reduces mitochondrial number and expression and activity of oxidative proteins in human skeletal muscle but that exercise-induced intracellular signaling as well as mRNA and microRNA (miR) responses are maintained after bed rest. Twelve young, healthy male subjects completed 7 days of bed rest with vastus lateralis muscle biopsies taken before and after bed rest. In addition, muscle biopsies were obtained from six of the subjects prior to, immediately after, and 3 h after 45 min of one-legged knee extensor exercise performed before and after bed rest. Maximal oxygen uptake decreased by 4%, and exercise endurance decreased nonsignificantly, by 11%, by bed rest. Bed rest reduced skeletal muscle mitochondrial DNA/nuclear DNA content 15%, hexokinase II and sirtuin 1 protein content ∼45%, 3-hydroxyacyl-CoA dehydrogenase and citrate synthase activity ∼8%, and miR-1 and miR-133a content ∼10%. However, cytochrome c and vascular endothelial growth factor (VEGF) protein content as well as capillarization did not change significantly with bed rest. Acute exercise increased AMP-activated protein kinase phosphorylation, peroxisome proliferator activated receptor-γ coactivator-1α, and VEGF mRNA content in skeletal muscle before bed rest, but the responses were abolished after bed rest. The present findings indicate that only 7 days of physical inactivity reduces skeletal muscle metabolic capacity as well as abolishes exercise-induced adaptive gene responses, likely reflecting an interference with the ability of skeletal muscle to adapt to exercise.

Enhanced sarcoplasmic reticulum Ca2+ release following intermittent sprint training

2000 ◽  
Vol 279 (1) ◽  
pp. R152-R160 ◽  
Author(s):  
Niels Ørtenblad ◽  
Per K. Lunde ◽  
Klaus Levin ◽  
Jesper L. Andersen ◽  
Preben K. Pedersen
Keyword(s):  
Sarcoplasmic Reticulum ◽  
High Intensity ◽  
Vastus Lateralis ◽  
Ryanodine Receptors ◽  
Vastus Lateralis Muscle ◽  
Sprint Training ◽  
High Intensity Training ◽  
Before And After ◽  
Muscle Biopsies ◽  
Intensity Training

To evaluate the effect of intermittent sprint training on sarcoplasmic reticulum (SR) function, nine young men performed a 5 wk high-intensity intermittent bicycle training, and six served as controls. SR function was evaluated from resting vastus lateralis muscle biopsies, before and after the training period. Intermittent sprint performance (ten 8-s all-out periods alternating with 32-s recovery) was enhanced 12% ( P < 0.01) after training. The 5-wk sprint training induced a significantly higher ( P < 0.05) peak rate of AgNO3-stimulated Ca2+ release from 709 (range 560–877; before) to 774 (596–977) arbitrary units Ca2+ ⋅ g protein− 1 ⋅ min− 1(after). The relative SR density of functional ryanodine receptors (RyR) remained unchanged after training; there was, however, a 48% ( P < 0.05) increase in total number of RyR. No significant differences in Ca2+ uptake rate and Ca2+-ATPase capacity were observed following the training, despite that the relative density of Ca2+-ATPase isoforms SERCA1 and SERCA2 had increased 41% and 55%, respectively ( P < 0.05). These data suggest that high-intensity training induces an enhanced peak SR Ca2+ release, due to an enhanced total volume of SR, whereas SR Ca2+ sequestration function is not altered.

Muscle glycogen availability and temperature regulation in humans

1989 ◽  
Vol 66 (1) ◽  
pp. 72-78 ◽  
Author(s):  
L. Martineau ◽  
I. Jacobs
Keyword(s):  
Skeletal Muscle ◽  
Muscle Glycogen ◽  
Temperature Regulation ◽  
Vastus Lateralis ◽  
Water Immersion ◽  
Vastus Lateralis Muscle ◽  
Glycogen Concentration ◽  
Exercise Regimen ◽  
Before And After ◽  
Muscle Groups

The effects of intramuscular glycogen availability on human temperature regulation were studied in eight seminude subjects immersed in 18 degrees C water for 90 min or until rectal temperature (Tre) decreased to 35.5 degrees C. Each subject was immersed three times over a 3-wk period. Each immersion followed 2.5 days of a specific dietary and/or exercise regimen designed to elicit low (L), normal (N), or high (H) glycogen levels in large skeletal muscle groups. Muscle glycogen concentration was determined in biopsies taken from the vastus lateralis muscle before and after each immersion. Intramuscular glycogen concentration before the immersion was significantly different among the L, N, and H trials (P less than 0.01), averaging 247 +/- 15, 406 +/- 23, and 548 +/- 42 (SE) mmol glucose units.kg dry muscle-1, respectively. The calculated metabolic heat production during the first 30 min of immersion was significantly lower during L compared with N or H (P less than 0.05). The rate at which Tre decreased was more rapid during the L immersion than either N or H (P less than 0.05), and the time during the immersion at which Tre first began to decrease also appeared sooner during L than N or H. The results suggest that low skeletal muscle glycogen levels are associated with more rapid body cooling during water immersion in humans. Higher than normal muscle glycogen levels, however, do not increase cold tolerance.

A single bout of exercise activates matrix metalloproteinase in human skeletal muscle

2007 ◽  
Vol 102 (6) ◽  
pp. 2346-2351 ◽  
Author(s):  
E. Rullman ◽  
H. Rundqvist ◽  
D. Wågsäter ◽  
H. Fischer ◽  
P. Eriksson ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Matrix Metalloproteinase ◽  
Vastus Lateralis ◽  
Tissue Expression ◽  
Tissue Inhibitor Of Metalloproteinase ◽  
Vastus Lateralis Muscle ◽  
Protein Levels ◽  
Single Bout ◽  
Exercise Induced ◽  
Muscle Biopsies

The aims of this study were 1) to characterize changes in matrix metalloproteinase (MMP), endostatin, and vascular endothelial growth factor (VEGF)-A expression in skeletal muscle in response to a single bout of exercise in humans; and 2) to determine if any exchange of endostatin and VEGF-A between circulation and the exercising leg is associated with a change in the tissue expression or plasma concentration of these factors. Ten healthy males performed 65 min of cycle exercise, and muscle biopsies were obtained from the vastus lateralis muscle at rest and immediately and 120 min after exercise. In the muscle biopsies, measurements of mRNA expression levels of MMP-2, MMP-9, MMP-14, and tissue inhibitor of metalloproteinase; VEGF and endostatin protein levels; and MMP activities were performed. Femoral arterial and venous concentrations of VEGF-A and endostatin were determined before, during, and 120 min after exercise. A single bout of exercise increased MMP-9 mRNA and activated MMP-9 protein in skeletal muscle. No measurable increase of endostatin was observed in the skeletal muscle or in plasma following exercise. A concurrent increase in skeletal muscle VEGF-A mRNA and protein levels was induced by exercise, with no signs of peripheral uptake from the circulation. However, a decrease in plasma VEGF-A concentration occurred following exercise. Thus 1) a single bout of exercise activated the MMP system without any resulting change in tissue endostatin protein levels, and 2) the increased VEGF-A protein levels are due to changes in the skeletal muscle tissue itself. Other mechanisms are responsible for the observed exercise-induced decrease in VEGF-A in plasma.

Phosphorylase a in human skeletal muscle during exercise and electrical stimulation

1978 ◽  
Vol 45 (6) ◽  
pp. 852-857 ◽  
Author(s):  
P. D. Gollnick ◽  
J. Karlsson ◽  
K. Piehl ◽  
B. Saltin
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Human Skeletal Muscle ◽  
Vastus Lateralis ◽  
Muscular Activity ◽  
Voluntary Exercise ◽  
Vastus Lateralis Muscle ◽  
Minor Importance ◽  
Muscle Lactate ◽  
Needle Technique

Experiments were conducted to examine the conversions of phosphorylase b to phosphorylase a in human skeletal muscle during bicycle exercise or isometric contractions. Muscle biopsies were obtained from the vastus lateralis with the needle technique at rest and either during or immediately after activity and frozen in liquid nitrogen within 2--4 s. Total phosphorylase and phosphorylase a activities were differentiated by measurement in the presence and absence of AMP, respectively. At rest 8.5% of the total phosphorylase activity existed in the a form. Little or no change in the percent of phosphorylase in the a form occurred during voluntary dynamic or static muscular activity that produced muscle lactate concentrations in excess of 18 mmol.kg-1 wet muscle. Electrical stimulation of the vastus lateralis muscle also failed to produce an increase in the percentage of phosphorylase a. These data suggest that during exercise the conversion of phosphorylase to the a form is of minor importance. An increased activity of phosphorylase b due to changes in muscle concentrations of ATP, AMP, and inorganic phosphate may regulate glycogenolysis during voluntary exercise in man.

scholarly journals Contractile activity-specific transcriptome response to acute endurance exercise and training in human skeletal muscle

2019 ◽  
Vol 316 (4) ◽  
pp. E605-E614 ◽  
Author(s):  
Daniil V. Popov ◽  
Pavel A. Makhnovskii ◽  
Elena I. Shagimardanova ◽  
Guzel R. Gazizova ◽  
Evgeny A. Lysenko ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Transcription Factors ◽  
Human Skeletal Muscle ◽  
Acute Exercise ◽  
Contractile Activity ◽  
Vastus Lateralis ◽  
Aerobic Exercise Training ◽  
Vastus Lateralis Muscle ◽  
Transcriptome Response ◽  
The One

Reduction in daily activity leads to dramatic metabolic disorders, while regular aerobic exercise training is effective for preventing this problem. The purpose of this study was to identify genes that are directly related to contractile activity in human skeletal muscle, regardless of the level of fitness. Transcriptome changes after the one-legged knee extension exercise in exercised and contralateral nonexercised vastus lateralis muscle of seven men were evaluated by RNA-seq. Transcriptome change at baseline after 2 mo of aerobic training (5/wk, 1 h/day) was evaluated as well. Postexercise changes in the transcriptome of exercised muscle were associated with different factors, including circadian oscillations. To reveal transcriptome response specific for endurance-like contractile activity, differentially expressed genes between exercised and nonexercised muscle were evaluated at 1 and 4 h after the one-legged exercise. The contractile activity-specific transcriptome responses were associated only with an increase in gene expression and were regulated mainly by CREB/ATF/AP1-, MYC/MAX-, and E2F-related transcription factors. Endurance training-induced changes (an increase or decrease) in the transcriptome at baseline were more pronounced than transcriptome responses specific for acute contractile activity. Changes after training were associated with widely different biological processes than those after acute exercise and were regulated by different transcription factors (IRF- and STAT-related factors). In conclusion, adaptation to regular exercise is associated not only with a transient (over several hours) increase in expression of many contractile activity-specific genes, but also with a pronounced change (an increase or decrease) in expression of a large number of genes under baseline conditions.

Eccentric exercise markedly increases c-Jun NH2-terminal kinase activity in human skeletal muscle

1999 ◽  
Vol 87 (5) ◽  
pp. 1668-1673 ◽  
Author(s):  
Marni D. Boppart ◽  
Doron Aronson ◽  
Lindsay Gibson ◽  
Ronenn Roubenoff ◽  
Leslie W. Abad ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Eccentric Exercise ◽  
Intracellular Signaling ◽  
Human Skeletal Muscle ◽  
Vastus Lateralis ◽  
Fold Increase ◽  
Mitogen Activated Protein Kinase ◽  
Eccentric Contractions ◽  
Vastus Lateralis Muscle

Eccentric contractions require the lengthening of skeletal muscle during force production and result in acute and prolonged muscle injury. Because a variety of stressors, including physical exercise and injury, can result in the activation of the c-Jun NH2-terminal kinase (JNK) intracellular signaling cascade in skeletal muscle, we investigated the effects of eccentric exercise on the activation of this stress-activated protein kinase in human skeletal muscle. Twelve healthy subjects (7 men, 5 women) completed maximal concentric or eccentric knee extensions on a KinCom isokinetic dynamometer (10 sets, 10 repetitions). Percutaneous needle biopsies were obtained from the vastus lateralis muscle 24 h before exercise (basal), immediately postexercise, and 6 h postexercise. Whereas both forms of exercise increased JNK activity immediately postexercise, eccentric contractions resulted in a much higher activation (15.4 ± 4.5 vs. 3.5 ± 1.4-fold increase above basal, eccentric vs. concentric). By 6 h after exercise, JNK activity decreased back to baseline values. In contrast to the greater activation of JNK with eccentric exercise, the mitogen-activated protein kinase kinase 4, the immediate upstream regulator of JNK, was similarly activated by concentric and eccentric exercise. Because the activation of JNK promotes the phosphorylation of a variety of transcription factors, including c-Jun, the results from this study suggest that JNK may be involved in the molecular and cellular adaptations that occur in response to injury-producing exercise in human skeletal muscle.

Effect of exercise on insulin action in human skeletal muscle

1989 ◽  
Vol 66 (2) ◽  
pp. 876-885 ◽  
Author(s):  
E. A. Richter ◽  
K. J. Mikines ◽  
H. Galbo ◽  
B. Kiens
Keyword(s):  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Insulin Action ◽  
Human Skeletal Muscle ◽  
Vastus Lateralis ◽  
Femoral Vein ◽  
Glycogen Synthesis ◽  
Vastus Lateralis Muscle ◽  
Glycogen Concentration ◽  
Local Contraction

The effect of 1 h of dynamic one-legged exercise on insulin action in human muscle was studied in 6 healthy young men. Four hours after one-legged knee extensions, a three-step sequential euglycemic hyperinsulinemic clamp combined with arterial and bilateral femoral vein catheterization was performed. Increased insulin action on glucose uptake was found in the exercised compared with the rested thigh at mean plasma insulin concentrations of 23, 40, and 410 microU/ml. Furthermore, prior contractions directed glucose uptake toward glycogen synthesis and increased insulin effects on thigh O2 consumption and at some insulin concentrations on potassium exchange. In contrast, no change in insulin effects on limb exchange of free fatty acids, glycerol, alanine or tyrosine were found after exercise. Glycogen concentration in rested vastus lateralis muscle did not increase measurably during the clamp even though indirect estimates indicated net glycogen synthesis. In contrast, in exercised muscle estimated and biopsy-verified increases in muscle glycogen concentration agreed. Local contraction-induced increases in insulin sensitivity and responsiveness play an important role in postexercise recovery of human skeletal muscle.

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