SKELETAL MUSCLE PLASMA MEMBRANE GLUCOSE TRANSPORT AND GLUCOSE TRANSPORTERS FOLLOWING EXERCISE.

1980 ◽  
Vol 21 (Supplement) ◽  
pp. S29
Author(s):  
L. J. Goodyear ◽  
M. F. Hirshman ◽  
P. A. King ◽  
E. D. Horton ◽  
E. S. Horton
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Glucose Transport ◽  
Glucose Transporters ◽  
Muscle Plasma Membrane

SKELETAL MUSCLE PLASMA MEMBRANE GLUCOSE TRANSPORT AND GLUCOSE TRANSPORTERS FOLLOWING EXERCISE.

1989 ◽  
Vol 21 (Supplement) ◽  
pp. S29
Author(s):  
L. J. Goodyear ◽  
M. F. Hirshman ◽  
P. A. King ◽  
E. D. Horton ◽  
E. S. Horton
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Glucose Transport ◽  
Glucose Transporters ◽  
Muscle Plasma Membrane

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.

Seasonal changes in plasma membrane glucose transporters enhance cryoprotectant distribution in the freeze-tolerant wood frog

1995 ◽  
Vol 73 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Patricia A. King ◽  
Mary N. Rosholt ◽  
Kenneth B. Storey
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Glucose Transport ◽  
Seasonal Changes ◽  
Plasma Membranes ◽  
Glucose Transporter ◽  
Glucose Transporters ◽  
Wood Frog ◽  
Maximal Velocity ◽  
Liver Membranes

One of the critical adaptations for freeze tolerance by the wood frog, Rana sylvatica, is the production of large quantities of glucose as an organ cryoprotectant during freezing exposures. Glucose export from the liver, where it is synthesized, and its uptake by other organs is dependent upon carrier-mediated transport across plasma membranes by glucose-transporter proteins. Seasonal changes in the capacity to transport glucose across plasma membranes were assessed in liver and skeletal muscle of wood frogs; summer-collected (June) frogs were compared with autumn-collected (September) cold-acclimated (5 °C for 3–4 weeks) frogs. Plasma membrane vesicles prepared from liver of autumn-collected frogs showed 6-fold higher rates of carrier-mediated glucose transport than vesicles from summer-collected frogs, maximal velocity (Vmax) values for transport being 72 ± 14 and 12.0 + 2.9 nmol∙mg protein−1∙s−1, respectively (at 10 °C). However, substrate affinity constants for carrier-mediated glucose transport (K1/2) did not change seasonally. The difference in transport rates was due to greater numbers of glucose transporters in liver plasma membranes from autumn-collected frogs. The total number of transporter sites, as determined by cytochalasin B binding, was 8.5-fold higher in autumn than in summer. Glucose transporters in wood frog liver membranes cross-reacted with antibodies to the rat GluT-2 glucose transporter (the mammalian liver isoform), and Western blots further confirmed a large increase in transporter numbers in liver membranes from autumn- versus summer-collected frogs. By contrast with the liver, however, there were no seasonal changes in glucose-transporter activity or numbers in plasma membranes isolated from skeletal muscle. We conclude that an enhanced capacity for glucose transport across liver, but not muscle, plasma membranes during autumn cold-hardening is an important adaptation that anticipates the need for rapid export of cryoprotectant from liver during natural freezing episodes.

scholarly journals Effects of glucocorticoid excess on the sensitivity of glucose transport and metabolism to insulin in rat skeletal muscle

1997 ◽  
Vol 321 (3) ◽  
pp. 707-712 ◽  
Author(s):  
George DIMITRIADIS ◽  
Brendan LEIGHTON ◽  
Mark PARRY-BILLINGS ◽  
Shlomo SASSON ◽  
Martin YOUNG ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Glucose Transport ◽  
Soleus Muscle ◽  
Glucose Oxidation ◽  
Glycogen Synthesis ◽  
Total Content ◽  
Glucose Transporters ◽  
Lactate Formation

This study examines the mechanisms of glucocorticoid-induced insulin resistance in rat soleus muscle. Glucocorticoid excess was induced by administration of dexamethasone to rats for 5 days. Dexamethasone decreased the sensitivity of 3-O-methylglucose transport, 2-deoxyglucose phosphorylation, glycogen synthesis and glucose oxidation to insulin. The total content of GLUT4 glucose transporters was not decreased by dexamethasone; however, the increase in these transporters in the plasma membrane in response to insulin (100 m-units/litre) was lessened. In contrast, the sensitivity of lactate formation to insulin was normal. The content of 2-deoxyglucose in the dexamethasone-treated muscle was decreased at 100 m-units/litre insulin, while the contents of glucose 6-phosphate and fructose 2,6-bisphosphate were normal at all concentrations of insulin studied. The maximal activity of hexokinase in the soleus muscle was not affected by dexamethasone; however, inhibition of this enzyme by glucose 6-phosphate was decreased. These results suggest the following. (1) Glucocorticoid excess causes insulin resistance in skeletal muscle by directly inhibiting the translocation of the GLUT4 glucose transporters to the plasma membrane in response to insulin; since the activity of hexokinase is not affected, the changes in the sensitivity of glucose phosphorylation to insulin seen under these conditions are secondary to those in glucose transport. (2) The sensitivity of glycogen synthesis and glucose oxidation to insulin is decreased, but that of glycolysis is not affected: a redistribution of glucose away from the pathway of glycogen synthesis and glucose oxidation could maintain a normal rate of lactate formation although the rate of glucose transport is decreased.

Glucose transport into rat skeletal muscle: interaction between exercise and insulin

1988 ◽  
Vol 65 (2) ◽  
pp. 909-913 ◽  
Author(s):  
H. Wallberg-Henriksson ◽  
S. H. Constable ◽  
D. A. Young ◽  
J. O. Holloszy
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Glucose Transport ◽  
Transport Process ◽  
Sugar Transport ◽  
Glucose Transporters ◽  
Mammalian Skeletal Muscle ◽  
Rat Skeletal Muscle ◽  
Wide Range ◽  
Exercise Induced

This study was done to evaluate the effect of insulin on sugar transport into skeletal muscle after exercise. The permeability of rat epitrochlearis muscle to 3-O-methylglucose (3-MG) was measured after exposure to a range of insulin concentrations 30, 60, and 180 min after a bout of exercise. Thirty and 60 min after exercise, the effects of exercise and insulin on 3-MG transport were additive over a wide range of insulin concentrations, with no increase in sensitivity or responsiveness to insulin. After 180 min, when approximately 66% of the exercise-induced increase in sugar transport had worn off, both the responsiveness and sensitivity of the glucose transport process to insulin were increased. These findings appear compatible with the hypothesis that the actions of exercise and insulin result in activation and/or translocation into the plasma membrane of two separate pools of glucose transporters in mammalian skeletal muscle.

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 Glycaemia regulates the glucose transporter number in the plasma membrane of rat skeletal muscle

1992 ◽  
Vol 284 (2) ◽  
pp. 341-348 ◽  
Author(s):  
D Dimitrakoudis ◽  
T Ramlal ◽  
S Rastogi ◽  
M Vranic ◽  
A Klip
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Glucose Transport ◽  
Transport System ◽  
Plasma Membranes ◽  
Glucose Transporter ◽  
Cytochalasin B ◽  
Glucose Transporters ◽  
Mrna Levels ◽  
Rat Skeletal Muscle

The number of glucose transporters was measured in isolated membranes from diabetic-rat skeletal muscle to determine the role of circulating blood glucose levels in the control of glucose uptake into skeletal muscle. Three experimental groups of animals were investigated in the post-absorptive state: normoglycaemic/normoinsulinaemic, hyperglycaemic/normoinsulinaemic and hyperglycaemic/normoinsulinaemic made normoglycaemic/normoinsulinaemic by phlorizin treatment. Hyperglycaemia caused a reversible decrease in total transporter number, as measured by cytochalasin B binding, in both plasma membranes and internal membranes of skeletal muscle. Changes in GLUT4 glucose transporter protein mirrored changes in cytochalasin B binding in plasma membranes. However, there was no recovery of GLUT4 levels in intracellular membranes with correction of glycaemia. GLUT4 mRNA levels decreased with hyperglycaemia and recovered only partially with correction of glycaemia. Conversely, GLUT1 glucose transporters were only detectable in the plasma membranes; the levels of this protein varied directly with glycaemia, i.e. in the opposite direction to GLUT4 glucose transporters. This study demonstrates that hyperglycaemia, in the absence of hypoinsulinaemia, is capable of down-regulating the glucose transport system in skeletal muscle, the major site of peripheral resistance to insulin-stimulated glucose transport in diabetes. Furthermore, correction of hyperglycaemia causes a complete restoration of the transport system in the basal state (determined by the transporter number in the plasma membrane), but possibly only an incomplete recovery of the transport system's ability to respond to insulin (since there is no recovery of GLUT4 levels in the intracellular membrane insulin-responsive transporter pool). Finally, the effect of hyperglycaemia is specific for glucose transporter isoforms, with GLUT1 and GLUT4 proteins varying respectively in parallel and opposite directions to levels of glycaemia.

Exercise training increases the number of glucose transporters in rat adipose cells

1989 ◽  
Vol 257 (4) ◽  
pp. E520-E530
Author(s):  
M. F. Hirshman ◽  
L. J. Wardzala ◽  
L. J. Goodyear ◽  
S. P. Fuller ◽  
E. D. Horton ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Glucose Transport ◽  
Glucose Transporters ◽  
Membrane Transporters ◽  
Control Group ◽  
Transport Activity ◽  
Insulin Stimulation ◽  
Adipose Cell ◽  
Adipose Cell Size ◽  
Adipose Cells

We studied the mechanism for the increase in glucose transport activity that occurs in adipose cells of exercise-trained rats. Glucose transport activity, glucose metabolism, and the subcellular distribution of glucose transporters were measured in adipose cells from rats raised in wheel cages for 6 wk (mean total exercise 350 km/rat), age-matched sedentary controls, and young sedentary controls matched for adipose cell size. Basal rates of glucose transport and metabolism were greater in cells from exercise-trained rats compared with young controls, and insulin-stimulated rates were greater in the exercise-trained rats compared with both age-matched and young controls. The numbers of plasma membrane glucose transporters were not different among groups in the basal state; however, with insulin stimulation, cells from exercise-trained animals had significantly more plasma membrane transporters than young controls or age-matched controls. Exercise-trained rats also had more low-density microsomal transporters than control rats in the basal state. When the total number of glucose transporters/cell was calculated, the exercise-trained rats had 42% more transporters than did either control group. These studies demonstrate that the increased glucose transport and metabolism observed in insulin-stimulated adipose cells from exercise-trained rats is due, primarily, to an increase in the number of plasma membrane glucose transporters translocated from an enlarged intracellular pool.

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