scholarly journals Chronic growth hormone treatment in normal rats reduces post-prandial skeletal muscle plasma membrane GLUT1 content, but not glucose transport or GLUT4 expression and localization

1996 ◽  
Vol 315 (3) ◽  
pp. 959-963 ◽  
Author(s):  
Raffaele NAPOLI ◽  
Antonio CITTADINI ◽  
Jesse C. CHOW ◽  
Michael F. HIRSHMAN ◽  
Robert J. SMITH ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Growth Hormone ◽  
Plasma Membrane ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Growth Hormone Treatment ◽  
Membrane Vesicles ◽  
Hormone Treatment ◽  
Plasma Membrane Vesicles ◽  
Muscle Glucose Transport

Whether skeletal muscle glucose transport system is impaired in the basal, post-prandial state during chronic growth hormone treatment is unknown. The current study was designed to determine whether 4 weeks of human growth hormone (hGH) treatment (3.5 mg/kg per day) would impair glucose transport and/or the number of glucose transporters in plasma membrane vesicles isolated from hindlimb skeletal muscle of Sprague–Dawley rats under basal, post-prandial conditions. hGH treatment was shown to have no effect on glucose influx (Vmax or Km) determined under equilibrium exchange conditions in isolated plasma membrane vesicles. Plasma membrane glucose transporter number (Ro) measured by cytochalasin B binding was also unchanged by hGH treatment. Consequently, glucose transporter turnover number (Vmax/Ro), a measure of average glucose transporter intrinsic activity, was similar in hGH-treated and control rats. hGH did not change GLUT4 protein content in whole muscle or in the plasma membrane, and muscle content of GLUT4 mRNA also was unchanged. In contrast, GLUT1 protein content in the plasma membrane fraction was significantly reduced by hGH treatment. This was associated with a modest, although not significant, decrease in muscle content of GLUT1 mRNA. In conclusion, high-dose hGH treatment for 4 weeks did not alter post-prandial skeletal muscle glucose transport activity. Neither the muscle level nor the intracellular localization of GLUT4 was changed by the hormone treatment. On the contrary, the basal post-prandial level of GLUT1 in the plasma membrane was reduced by hGH. The mRNA data suggest that this reduction might result from a decrease in the synthesis of GLUT1.

Skeletal muscle plasma membrane glucose transport and glucose transporters after exercise

1990 ◽  
Vol 68 (1) ◽  
pp. 193-198 ◽  
Author(s):  
L. J. Goodyear ◽  
M. F. Hirshman ◽  
P. A. King ◽  
E. D. Horton ◽  
C. M. Thompson ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Glucose Uptake ◽  
Glucose Transport ◽  
Time Course ◽  
Plasma Membranes ◽  
Glucose Transporter ◽  
Male Rats ◽  
Intrinsic Activity ◽  
Plasma Membrane Vesicles

Recent reports have shown that immediately after an acute bout of exercise the glucose transport system of rat skeletal muscle plasma membranes is characterized by an increase in both glucose transporter number and intrinsic activity. To determine the duration of the exercise response we examined the time course of these changes after completion of a single bout of exercise. Male rats were exercised on a treadmill for 1 h (20 m/min, 10% grade) or allowed to remain sedentary. Rats were killed either immediately or 0.5 or 2 h after exercise, and red gastrocnemius muscle was used for the preparation of plasma membranes. Plasma membrane glucose transporter number was elevated 1.8- and 1.6-fold immediately and 30 min after exercise, although facilitated D-glucose transport in plasma membrane vesicles was elevated 4- and 1.8-fold immediately and 30 min after exercise, respectively. By 2 h after exercise both glucose transporter number and transport activity had returned to nonexercised control values. Additional experiments measuring glucose uptake in perfused hindquarter muscle produced similar results. We conclude that the reversal of the increase in glucose uptake by hindquarter skeletal muscle after exercise is correlated with a reversal of the increase in the glucose transporter number and activity in the plasma membrane. The time course of the transport-to-transporter ratio suggests that the intrinsic activity response reverses more rapidly than that involving transporter number.

High-fat diet reduces glucose transporter responses to both insulin and exercise

1994 ◽  
Vol 266 (1) ◽  
pp. R95-R101 ◽  
Author(s):  
M. N. Rosholt ◽  
P. A. King ◽  
E. S. Horton
Keyword(s):  
Insulin Resistance ◽  
Plasma Membrane ◽  
Glucose Transport ◽  
High Fat Diet ◽  
Glucose Transporter ◽  
Membrane Vesicles ◽  
Intrinsic Activity ◽  
Sprague Dawley ◽  
High Fat ◽  
Plasma Membrane Vesicles

High-fat diet (HFD) induces skeletal muscle insulin resistance. To investigate associated changes in the plasma membrane glucose transporter, male Sprague-Dawley rats were fed either chow [high-carbohydrate diet (HCD)] or HFD for 3 wk. Plasma membrane vesicles were prepared from hindlimb muscle of control, insulin-stimulated (Ins), and acutely exercised (Ex) rats. Maximal vesicle glucose transport activity (Vmax) increased threefold with Ins and Ex treatment compared with controls in HCD rats; in HFD rats, increases were less than twofold. Transporter numbers (measured by cytochalasin B binding, CB) approximately doubled with Ins and Ex in both diet groups. Intrinsic activity (carrier turnover, Vmax/CB) increased significantly with stimulation in HCD but not HFD rats. Therefore, vesicles from HFD rats showed resistance to both exercise and insulin stimulation of muscle glucose transport. Transporter number increased normally, but intrinsic activity in HFD rats did not respond. Two conclusions are discussed: 1) translocation and activation are distinct, separable steps in transporter stimulation and 2) HFD produces effects that resemble the insulin resistance of starvation.

Contractile activity increases plasma membrane glucose transporters in absence of insulin

1990 ◽  
Vol 258 (4) ◽  
pp. E667-E672 ◽  
Author(s):  
L. J. Goodyear ◽  
P. A. King ◽  
M. F. Hirshman ◽  
C. M. Thompson ◽  
E. D. Horton ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Contractile Activity ◽  
Male Rats ◽  
Intrinsic Activity ◽  
Plasma Membrane Vesicle ◽  
Muscle Plasma Membrane ◽  
Muscle Glucose Transport

To study the interactions between insulin and contraction on the skeletal muscle glucose transport system, the hindquarters of male rats were perfused in the absence of insulin, in the presence of insulin (30 mU/ml), during contractions induced by sciatic nerve stimulation, or during contractions plus insulin. Compared with control preparations, rates of glucose uptake in the perfused hindquarter were increased by 2.5- and 2.6-fold in the insulin and insulin plus contraction groups, respectively, but not significantly increased in the contraction only preparations. After perfusion, soleus and red and white gastrocnemius muscles from the hindquarter were pooled and used for the preparation of plasma membranes. Skeletal muscle plasma membrane vesicle glucose transport rates were 2.2 +/- 0.5, 7.9 +/- 1.7, 9.0 +/- 2.2, and 10.8 +/- 2.0 nmol.mg protein-1.s-1 (40 mM glucose), and plasma membrane glucose transporter numbers were 4.7 +/- 0.5, 8.1 +/- 0.9, 9.1 +/- 1.0, and 8.6 +/- 0.6 pmol/mg protein in the control, contraction, insulin, and insulin plus contraction groups, respectively. The transport-transporter ratio, an indication of plasma membrane glucose transporter intrinsic activity, was increased by contraction, insulin, and insulin plus contraction. These results demonstrate that contractile activity in the absence of insulin increases muscle plasma membrane glucose transport by increasing transporter number and intrinsic activity. In addition, under these experimental conditions, the effects of insulin and contraction to increase muscle glucose transport are not additive.

scholarly journals Skeletal Muscle Glucose Transport and Metabolism Are Enhanced in Transgenic Mice Overexpressing the Glut4 Glucose Transporter.

1995 ◽  
Vol 270 (4) ◽  
pp. 1679-1684
Author(s):  
Polly A. Hansen ◽  
Eric A. Gulve ◽  
Bess Adkins Marshall ◽  
Jiaping Gao ◽  
Jeffrey E. Pessin ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Transgenic Mice ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Muscle Glucose Transport

Expression and cellular localization of glucose transporters (GLUT1, GLUT3, GLUT4) during differentiation of myogenic cells isolated from rat foetuses

1994 ◽  
Vol 107 (3) ◽  
pp. 487-496 ◽  
Author(s):  
I. Guillet-Deniau ◽  
A. Leturque ◽  
J. Girard
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Glucose Transport ◽  
Cell Fusion ◽  
Cellular Localization ◽  
Glucose Transporter ◽  
Glucose Transporters ◽  
Short Exposure ◽  
Myoblast Differentiation ◽  
Igf I

Skeletal muscle regeneration is mediated by the proliferation of myoblasts from stem cells located beneath the basal lamina of myofibres, the muscle satellite cells. They are functionally indistinguishable from embryonic myoblasts. The myogenic process includes the fusion of myoblasts into multinucleated myotubes, the biosynthesis of proteins specific for skeletal muscle and proteins that regulates glucose metabolism, the glucose transporters. We find that three isoforms of glucose transporter are expressed during foetal myoblast differentiation: GLUT1, GLUT3 and GLUT4; their relative expression being dependent upon the stage of differentiation of the cells. GLUT1 mRNA and protein were abundant only in myoblasts from 19-day-old rat foetuses or from adult muscles. GLUT3 mRNA and protein, detectable in both cell types, increased markedly during cell fusion, but decreased in contracting myotubes. GLUT4 mRNA and protein were not expressed in myoblasts. They appeared only in spontaneously contracting myotubes cultured on an extracellular matrix. Insulin or IGF-I had no effect on the expression of the three glucose transporter isoforms, even in the absence of glucose. The rate of glucose transport, assessed using 2-[3H]deoxyglucose, was 2-fold higher in myotubes than in myoblasts. Glucose deprivation increased the basal rate of glucose transport by 2-fold in myoblasts, and 4-fold in myotubes. The cellular localization of the glucose transporters was directly examined by immunofluorescence staining. GLUT1 was located on the plasma membrane of myoblasts and myotubes. GLUT3 was located intracellularly in myoblasts and appeared also on the plasma membrane in myotubes. Insulin or IGF-I were unable to target GLUT3 to the plasma membrane. GLUT4, the insulin-regulatable glucose transporter isoform, appeared only in contracting myotubes in small intracellular vesicles. It was translocated to the plasma membrane after a short exposure to insulin, as it is in skeletal muscle in vivo. These results show that there is a switch in glucose transporter isoform expression during myogenic differentiation, dependent upon the energy required by the different stages of the process. GLUT3 seemed to play a role during cell fusion, and could be a marker for the muscle's ability to regenerate.

Kinetics of glucose transport in rat skeletal muscle membrane vesicles: effects of insulin and contractions

1992 ◽  
Vol 262 (5) ◽  
pp. E700-E711 ◽  
Author(s):  
T. Ploug ◽  
H. Galbo ◽  
T. Ohkuwa ◽  
J. Tranum-Jensen ◽  
J. Vinten
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Glucose Transport ◽  
Cytochalasin B ◽  
Equilibrium Distribution ◽  
Initial Rate ◽  
Membrane Vesicles ◽  
Membrane Preparation ◽  
Muscle Membrane ◽  
Distribution Space

To study the mechanism of acceleration of glucose transport in skeletal muscle after stimulation with insulin and contractions, we isolated a subcellular vesicular membrane fraction, highly enriched in the plasma membrane enzyme K(+)-stimulated p-nitrophenylphosphatase and also enriched in some intracellular membranes. Protein recovery, morphology, lipid content, marker enzyme activities, total intravesicular volume, Western blot quantitation of GLUT-1, and glucose-inhibitable cytochalasin B binding were identical in membrane fractions from control, insulin-stimulated, contraction-stimulated, and insulin- and contraction-stimulated muscle. Time course of D-[3H]glucose entry in membrane vesicles at equilibrium exchange conditions showed that initial rate of transport at 30 mM of glucose was increased 19-fold and that equilibrium distribution space was increased 4-fold in vesicles from maximum stimulated muscle. The effects of insulin and contractions on initial rate of transport as well as on equilibrium distribution space were additive, and stimulation increased the substrate saturability of glucose transport. Furthermore, cytochalasin B binding to membranes prepared by using less centrifugation time than usual showed that, after stimulation with insulin and contractions, at least 35% of the total number of glucose transporters were redistributed from one kind of vesicles to a more slowly sedimenting kind of vesicles, probably reflecting translocation within the membrane preparation from intracellular vesicles to the plasma membrane upon stimulation. In the present membrane preparation the effects of insulin and/or contractions on glucose transport resemble those seen in intact muscle, and the effects are thus not dependent on cellular integrity.(ABSTRACT TRUNCATED AT 250 WORDS)

Stimulation of glucose transport in skeletal muscle by hypoxia

1991 ◽  
Vol 70 (4) ◽  
pp. 1593-1600 ◽  
Author(s):  
G. D. Cartee ◽  
A. G. Douen ◽  
T. Ramlal ◽  
A. Klip ◽  
J. O. Holloszy
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Muscle Contraction ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Cytochalasin B ◽  
Sugar Transport ◽  
Transport Activity ◽  
Hindlimb Muscles ◽  
Stimulation Of

Hypoxia caused a progressive cytochalasin B-inhibitable increase in the rate of 3-O-methylglucose transport in rat epitrochlearis muscles to a level approximately six-fold above basal. Muscle ATP concentration was well maintained during hypoxia, and increased glucose transport activity was still present after 15 min of reoxygenation despite repletion of phosphocreatine. However, the increase in glucose transport activity completely reversed during a 180-min-long recovery in oxygenated medium. In perfused rat hindlimb muscles, hypoxia caused an increase in glucose transporters in the plasma membrane, suggesting that glucose transporter translocation plays a role in the stimulation of glucose transport by hypoxia. The maximal effects of hypoxia and insulin on glucose transport activity were additive, whereas the effects of exercise and hypoxia were not, providing evidence suggesting that hypoxia and exercise stimulate glucose transport by the same mechanism. Caffeine, at a concentration too low to cause muscle contraction or an increase in glucose transport by itself, markedly potentiated the effect of a submaximal hypoxic stimulus on sugar transport. Dantrolene significantly inhibited the hypoxia-induced increase in 3-O-methylglucose transport. These effects of caffeine and dantrolene suggest that Ca2+ plays a role in the stimulation of glucose transport by hypoxia.

Effects of Caloric Restriction and Growth Hormone Treatment on Insulin‐Related Intermediates in The Skeletal Muscle

2008 ◽  
Vol 22 (S2) ◽  
pp. 116-116
Author(s):  
Khalid A Al‐Regaiey ◽  
Michal M Masternak ◽  
Zhihui Wang ◽  
Jacob Panici ◽  
Andrzej Bartke
Keyword(s):  
Skeletal Muscle ◽  
Growth Hormone ◽  
Caloric Restriction ◽  
Growth Hormone Treatment ◽  
Hormone Treatment

Protein turnover in rat skeletal muscle: effects of hypophysectomy and growth hormone.

1978 ◽  
Vol 234 (1) ◽  
pp. E38 ◽  
Author(s):  
K E Flaim ◽  
J B Li ◽  
L S Jefferson
Keyword(s):  
Skeletal Muscle ◽  
Growth Hormone ◽  
Protein Synthesis ◽  
Protein Turnover ◽  
Gastrocnemius Muscle ◽  
Growth Hormone Treatment ◽  
Hormone Replacement ◽  
Hormone Treatment ◽  
Rat Skeletal Muscle

The role of growth hormone in regulating protein turnover was examined in a perfused preparation of rat skeletal muscle. The perfused muscle maintained in vivo levels of ATP and creatine phosphate and exhibited constant rates of oxygen consumption and protein synthesis. Hypophysectomy reduced the rate of protein synthesis, the concentration of RNA, and the efficiency of protein synthesis in gastrocnemius muscle to 30, 46, and 66 percent of normal, respectively. In vivo treatment of hypophysectomized (hypox) rats with bovine growth hormone (250 microgram/day for 5 days) resulted in small increases in protein synthesis and RNA, whereas synthesis/RNA was returned to near normal. Elevation of ribosomal subunits in psoas muscle indicated an inhibition of peptide-chain initiation in hypox rats that was reversed by in vivo growth hormone treatment. Thus, hypox rats exhibited both a decreased capacity and a decreased efficiency of protein synthesis. Growth hormone replacement primarily increased efficiency of protein synthesis. The rate of protein degradation and the activity of cathepsin D in gastrocnemius muscle were decreased by hypophysectomy. Growth hormone treatment had no significant effect on degradation.

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