Effect of hormonal and substrate backgrounds on cell membrane function in normal males

1987 ◽  
Vol 63 (3) ◽  
pp. 1107-1113 ◽  
Author(s):  
G. A. Fantini ◽  
J. P. Roberts ◽  
S. F. Lowry ◽  
J. D. Albert ◽  
K. J. Tracey ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Vastus Lateralis ◽  
Cellular Membrane ◽  
Resting Membrane Potential ◽  
Vastus Lateralis Muscle ◽  
Epinephrine Infusion ◽  
Membrane Function ◽  
Tibialis Muscle ◽  
Group B

Hormonal and substrate influences on in vivo cellular membrane function were evaluated in 15 healthy male volunteers. Each subject underwent serial evaluations of membrane function in the anterior tibialis muscle, as assessed by transcutaneous measurement of resting membrane potential (Em). Group A subjects (n = 9) underwent measurement of resting Em in the basal state and again during the 10th day of intravenous feeding (IVF). Group B subjects (n = 6) underwent measurement of resting Em in the basal state during epinephrine infusion and again during epinephrine infusion on the 7th day of IVF. Percutaneous needle biopsy of the vastus lateralis muscle permitted calculation of transmembrane electrolyte distribution from the Nernst equation, using the measured Em and the chloride space method. Hospitalization with intake of a defined-formula enteral diet for 3 days resulted in depolarization (P less than 0.05) of resting Em (-75.3 +/- 1.6 mV) compared with normal (-79.8 +/- 0.9 mV). Despite 10 days of subsequent IVF, further depolarization (P less than 0.05) of resting Em (-71.2 +/- 1.2 mV) was observed. In the dual presence of IVF and exogenous epinephrine infusion, there was an increase (P less than 0.05) in intracellular potassium concentration and repolarization of resting Em (-80.6 +/- 0.8 mV) to normal levels. These data indicate that hormonal background and substrate availability contribute to the in vivo modulation of cellular membrane function in human skeletal muscle, possibly through facilitation of sodium-dependent amino acid transport across the cell membrane.

In vivo estimation of contraction velocity of human vastus lateralis muscle during “isokinetic” action

2000 ◽  
Vol 88 (3) ◽  
pp. 851-856 ◽  
Author(s):  
Y. Ichinose ◽  
Y. Kawakami ◽  
M. Ito ◽  
H. Kanehisa ◽  
T. Fukunaga
Keyword(s):  
Angular Velocity ◽  
Vastus Lateralis ◽  
Knee Extension ◽  
Vastus Lateralis Muscle ◽  
Shortening Velocity ◽  
Full Extension ◽  
Fascicle Length ◽  
Lateralis Muscle ◽  
Angular Velocities

To determine the shortening velocities of fascicles of the vastus lateralis muscle (VL) during isokinetic knee extension, six male subjects were requested to extend the knee with maximal effort at angular velocities of 30 and 150°/s. By using an ultrasonic apparatus, longitudinal images of the VL were produced every 30 ms during knee extension, and the fascicle length and angle of pennation were obtained from these images. The shortening fascicle length with extension of the knee (from 98 to 13° of knee angle; full extension = 0°) was greater (43 mm) at 30°/s than at 150°/s (35 mm). Even when the angular velocity remained constant during the isokinetic range of motion, the fascicle velocity was found to change from 39 to 77 mm/s at 150°/s and from 6 to 19 mm/s at 30°/s. The force exerted by a fascicle changed with the length of the fascicle at changing angular velocities. The peak values of fascicle force and velocity were observed at ∼90 mm of fascicle length. In conclusion, even if the angular velocity of knee extension is kept constant, the shortening velocity of a fascicle is dependent on the force applied to the muscle-tendon complex, and the phenomenon is considered to be caused mainly by the elongation of the elastic element (tendinous tissue).

Additive effects of cortisol and growth hormone on regional and systemic lipolysis in humans

2004 ◽  
Vol 286 (3) ◽  
pp. E488-E494 ◽  
Author(s):  
C. B. Djurhuus ◽  
C. H. Gravholt ◽  
S. Nielsen ◽  
S. B. Pedersen ◽  
N. Møller ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Adipose Tissue ◽  
Vastus Lateralis ◽  
Vastus Lateralis Muscle ◽  
Additive Effects ◽  
Subcutaneous Adipose ◽  
In Vivo Effects ◽  
Circulating Levels

Growth hormone (GH) and cortisol are important to ensure energy supplies during fasting and stress. In vitro experiments have raised the question whether GH and cortisol mutually potentiate lipolysis. In the present study, combined in vivo effects of GH and cortisol on adipose and muscle tissue were explored. Seven lean males were examined four times over 510 min. Microdialysis catheters were inserted in the vastus lateralis muscle and in the subcutaneous adipose tissue of the thigh and abdomen. A pancreatic-pituitary clamp was maintained with somatostatin infusion and replacement of GH, insulin, and glucagon at baseline levels. At t = 150 min, administration was performed of NaCl (I), a 2 μg·kg-1·min-1hydrocortisone infusion (II), a 200-μg bolus of GH (III), or a combination of II and III (IV). Systemic free fatty acid (FFA) turnover was estimated by [9,10-3H]palmitate appearance. Circulating levels of glucose, insulin, and glucagon were comparable in I-IV. GH levels were similar in I and II (0.50 ± 0.08 μg/l, mean ± SE). Peak levels during III and IV were ∼9 μg/l. Cortisol levels rose to ∼900 nmol/l in II and IV. Systemic (i.e., palmitate fluxes, s-FFA, s-glycerol) and regional (interstitial adipose tissue and skeletal muscle) markers of lipolysis increased in response to both II and III. In IV, they were higher and equal to the isolated additive effects of the two hormones. In conclusion, we find that GH and cortisol stimulate systemic and regional lipolysis independently and in an additive manner when coadministered. On the basis of previous studies, we speculate that the mode of action is mediated though different pathways.

scholarly journals In vivo activation of ROCK1 by insulin is impaired in skeletal muscle of humans with type 2 diabetes

2011 ◽  
Vol 300 (3) ◽  
pp. E536-E542 ◽  
Author(s):  
Kwang-Hoon Chun ◽  
Kang-Duk Choi ◽  
Dae-Ho Lee ◽  
YoonShin Jung ◽  
Robert R. Henry ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Kinase Domain ◽  
Glucose Disposal ◽  
Vastus Lateralis Muscle ◽  
Protein Levels ◽  
Resistance To Insulin ◽  
Obese Subjects ◽  
Type 2 Diabetic

To determine whether serine/threonine ROCK1 is activated by insulin in vivo in humans and whether impaired activation of ROCK1 could play a role in the pathogenesis of insulin resistance, we measured the activity of ROCK1 and the protein content of the Rho family in vastus lateralis muscle of lean, obese nondiabetic, and obese type 2 diabetic subjects. Biopsies were taken after an overnight fast and after a 3-h hyperinsulinemic euglycemic clamp. Insulin-stimulated GDR was reduced 38% in obese nondiabetic subjects compared with lean, 62% in obese diabetic subjects compared with lean, and 39% in obese diabetic compared with obese nondiabetic subjects (all comparisons P < 0.001). Insulin-stimulated IRS-1 tyrosine phosphorylation is impaired 41–48% in diabetic subjects compared with lean or obese subjects. Basal activity of ROCK1 was similar in all groups. Insulin increased ROCK1 activity 2.1-fold in lean and 1.7-fold in obese nondiabetic subjects in muscle. However, ROCK1 activity did not increase in response to insulin in muscle of obese type 2 diabetic subjects without change in ROCK1 protein levels. Importantly, insulin-stimulated ROCK1 activity was positively correlated with insulin-mediated GDR in lean subjects ( P < 0.01) but not in obese or type 2 diabetic subjects. Moreover, RhoE GTPase that inhibits the catalytic activity of ROCK1 by binding to the kinase domain of the enzyme is notably increased in obese type 2 diabetic subjects, accounting for defective ROCK1 activity. Thus, these data suggest that ROCK1 may play an important role in the pathogenesis of resistance to insulin action on glucose disposal in muscle of obese type 2 diabetic subjects.

scholarly journals Proliferation of Human Primary Myoblasts Is Associated with Altered Energy Metabolism in Dependence on AgeingIn VivoandIn Vitro

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Reedik Pääsuke ◽  
Margus Eimre ◽  
Andres Piirsoo ◽  
Nadežda Peet ◽  
Liidia Laada ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Satellite Cells ◽  
Vastus Lateralis ◽  
Enzyme Analysis ◽  
Vastus Lateralis Muscle ◽  
Low Grade ◽  
Older Individuals ◽  
Older Subjects

Background. Ageing is associated with suppressed regenerative potential of muscle precursor cells due to decrease of satellite cells and suppressive intramuscular milieu on their activation, associated with ageing-related low-grade inflammation. The aim of the study was to characterize the function of oxidative phosphorylation (OXPHOS), glycolysis, adenylate kinase (AK), and creatine kinase (CK) mediated systems in young and older individuals.Materials and Methods. Myoblasts were cultivated from biopsies taken by transcutaneous conchotomy from vastus lateralis muscle in young (20–29 yrs,n=7) and older (70–79 yrs,n=7) subjects. Energy metabolism was assessed in passages 2 to 6 by oxygraphy and enzyme analysis.Results. In myoblasts of young and older subjects the rate of OXPHOS decreased during proliferation from passages 2 to 6. The total activities of CK and AK decreased. Myoblasts of passage 2 cultivated from young muscle showed higher rate of OXPHOS and activities of CK and AK compared to myoblasts from older subjects while hexokinase and pyruvate kinase were not affected by ageing.Conclusions. Proliferation of myoblastsin vitrois associated with downregulation of OXPHOS and energy storage and transfer systems. Ageingin vivoexerts an impact on satellite cells which results in altered metabolic profile in favour of the prevalence of glycolytic pathways over mitochondrial OXPHOS of myoblasts.

Calpain-3 is autolyzed and hence activated in human skeletal muscle 24 h following a single bout of eccentric exercise

2007 ◽  
Vol 103 (3) ◽  
pp. 926-931 ◽  
Author(s):  
Robyn M. Murphy ◽  
Craig A. Goodman ◽  
Michael J. McKenna ◽  
Jason Bennie ◽  
Murray Leikis ◽  
...  
Keyword(s):  
Eccentric Exercise ◽  
Human Subjects ◽  
Vastus Lateralis ◽  
Venous Blood ◽  
Knee Extensor ◽  
Vastus Lateralis Muscle ◽  
Healthy Human ◽  
Calpain 3 ◽  
Torque Measurements

The function and normal regulation of calpain-3, a muscle-specific Ca2+-dependent protease, is uncertain, although its absence leads to limb-girdle muscular dystrophy type 2A. This study examined the effect of eccentric exercise on calpain-3 autolytic activation, because such exercise is known to damage sarcomeric structures and to trigger adaptive changes that help prevent such damage on subsequent exercise. Six healthy human subjects performed a 30-min bout of one-legged, eccentric, knee extensor exercise. Torque measurements, vastus lateralis muscle biopsies, and venous blood samples were taken before and up to 7 days following the exercise. Peak isometric muscle torque was depressed immediately and at 3 h postexercise and recovered by 24 h, and serum creatine kinase concentration peaked at 24 h postexercise. The amount of autolyzed calpain-3 was unchanged immediately and 3 h after exercise, but increased markedly (from ∼16% to ∼35% of total) 24 h after the exercise, and returned to preexercise levels within 7 days. In contrast, the eccentric exercise produced little autolytic activation of the ubiquitous Ca2+-activated protease, μ-calpain. Eccentric exercise is the first physiological circumstance shown to result in calpain-3 activation in vivo.

In vivo behavior of vastus lateralis muscle during dynamic performances

2001 ◽  
Vol 1 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Taija Finni ◽  
Shigeki Ikegaw ◽  
Vesa Lepola ◽  
Paavo Komi
Keyword(s):  
Vastus Lateralis ◽  
Vastus Lateralis Muscle ◽  
Lateralis Muscle ◽  
Dynamic Performances

scholarly journals The rate of substrate cycling between fructose 6-phosphate and fructose 1,6-bisphosphate in skeletal muscle from cold-exposed, hyperthyroid or acutely exercised rats

1985 ◽  
Vol 231 (1) ◽  
pp. 217-220 ◽  
Author(s):  
R A J Challis ◽  
J R S Arch ◽  
E A Newsholme
Keyword(s):  
Cold Exposure ◽  
Acute Exercise ◽  
Vastus Lateralis ◽  
Exercise Bout ◽  
Vastus Lateralis Muscle ◽  
Hyperthyroid State ◽  
Fructose 1,6 Bisphosphatase ◽  
Fructose 1,6 Bisphosphate

The effects of cold-exposure, the hyperthyroid state and a single exercise bout in vivo on the maximal enzyme activities of 6-phosphofructokinase and fructose-1,6-bisphosphatase in vastus lateralis muscle and the rates of fructose 6-phosphate/fructose 1,6-bisphosphate cycling measured in epitrochlearis muscle in vitro were investigated. In all cases significant changes in substrate cycling rates were observed, whether in the absence of added hormones in vitro (acute exercise), or when stimulated by insulin plus adrenaline (cold-exposure), or with respect to the catecholamine-sensitivity of the cycling rate (the hyperthyroid state).

Determining the Force-Length-Velocity Relations of the Quadriceps Muscles: I. Anatomical and Geometric Parameters

1999 ◽  
Vol 15 (2) ◽  
pp. 182-190 ◽  
Author(s):  
John W. Chow ◽  
Warren G. Darling ◽  
James C. Ehrhardt
Keyword(s):  
Magnetic Resonance ◽  
Knee Flexion ◽  
Vastus Lateralis ◽  
Quadriceps Muscle ◽  
Vastus Lateralis Muscle ◽  
Moment Arm ◽  
Anatomical Position ◽  
Moment Arms ◽  
Effective Moment

The purpose of this study was to determine the coordinates of the origin and insertion, muscle volumes, lengths, lines of action, and effective moment arm of the quadriceps muscles in vivo using magnetic resonance imaging (MRI) and radiography for a pilot study involving musculoskeletal modeling. Two magnetic resonance scans were performed, and axial images were obtained for the left thigh of a female subject in the anatomical position to measure muscle volume, coordinates of the origin and insertion, and muscle belly length at the anatomical position of each quadriceps muscle. Six knee radiographs were used to determine the effective moment arm of the quadriceps force at different knee flexion angles. A combination of MRI and radiography data was used to compute the muscle lengths at different knee flexion angles. The coordinates of the vastus lateralis, muscle volumes of individual quadriceps muscles, and effective moment arms were clearly different from the corresponding values from cadaver data reported in the literature. These comparisons demonstrate the advantages of using personalized muscle parameters instead of those collected from cadavers and dry-bone specimens.

Effects of isometric training on the elasticity of human tendon structures in vivo

2001 ◽  
Vol 91 (1) ◽  
pp. 26-32 ◽  
Author(s):  
Keitaro Kubo ◽  
Hiroaki Kanehisa ◽  
Masamitsu Ito ◽  
Tetsuo Fukunaga
Keyword(s):  
Vastus Lateralis ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Vastus Lateralis Muscle ◽  
Electromechanical Delay ◽  
Isometric Training ◽  
Rate Of Torque Development ◽  
Human Tendon ◽  
Torque Development

The present study aimed to investigate the effect of isometric training on the elasticity of human tendon structures. Eight subjects completed 12 wk (4 days/wk) of isometric training that consisted of unilateral knee extension at 70% of maximal voluntary contraction (MVC) for 20 s per set (4 sets/day). Before and after training, the elongation of the tendon structures in the vastus lateralis muscle was directly measured using ultrasonography while the subjects performed ramp isometric knee extension up to MVC. The relationship between the estimated muscle force and tendon elongation ( L) was fitted to a linear regression, the slope of which was defined as stiffness of the tendon structures. The training increased significantly the volume (7.6±4.3%) and MVC torque (33.9±14.4%) of quadriceps femoris muscle. The L values at force production levels beyond 550 N were significantly shorter after training. The stiffness increased significantly from 67.5±21.3 to 106.2±33.4 N/mm. Furthermore, the training significantly increased the rate of torque development (35.8 ± 20.4%) and decreased electromechanical delay (−18.4±3.8%). Thus the present results indicate that isometric training increases the stiffness and Young's modulus of human tendon structures as well as muscle strength and size. This change in the tendon structures would be assumed to be an advantage for increasing the rate of torque development and shortening the electromechanical delay.

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