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

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.

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Reversal of enhanced muscle glucose transport after exercise: roles of insulin and glucose

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1990.259.5.e685 ◽

1990 ◽

Vol 259 (5) ◽

pp. E685-E691 ◽

Cited By ~ 22

Author(s):

E. A. Gulve ◽

G. D. Cartee ◽

J. R. Zierath ◽

V. M. Corpus ◽

J. O. Holloszy

Keyword(s):

Skeletal Muscle ◽

Insulin Sensitivity ◽

Glucose Transport ◽

Transport Process ◽

Sugar Transport ◽

Transport Activity ◽

High Concentration ◽

Exercise Induced ◽

Muscle Glucose Transport

Exercise stimulates insulin-independent glucose transport in skeletal muscle and also increases the sensitivity of the glucose transport process in muscle to insulin. A previous study [D. A. Young, H. Wallberg-Henriksson, M. D. Sleeper, and J. O. Holloszy. Am. J. Physiol. 253 (Endocrinol. Metab. 16): E331–E335, 1987] showed that the exercise-induced increase in glucose transport activity disappears rapidly when rat epitrochlearis muscles are incubated for 3 h in vitro in the absence of insulin and that 7.5 microU/ml insulin in the incubation medium apparently slowed the loss of enhanced sugar transport. We examined whether addition of insulin several hours after exercise increases glucose transport to the same extent as continuous insulin exposure. Addition of 7.5 microU/ml insulin 2.5 h after exercise (when glucose transport has returned to basal levels) increased sugar transport to the same level as that which resulted from continuous insulin exposure. This finding provides evidence for an increase in insulin sensitivity rather than a slowing of reversal of the exercise-induced increase in insulin-independent glucose transport activity. Glucose transport was enhanced only at submaximal, not at maximal, insulin concentrations. Exposure to a high concentration of glucose and a low insulin concentration reduced the exercise-induced increase in insulin-sensitive glucose transport. Incubation with a high concentration of 2-deoxy-D-glucose (2-DG) did not alter the increase in insulin sensitivity, even though a large amount of 2-DG entered the muscle and was phosphorylated.(ABSTRACT TRUNCATED AT 250 WORDS)

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

Biochemical Journal ◽

10.1042/bj2840341 ◽

1992 ◽

Vol 284 (2) ◽

pp. 341-348 ◽

Cited By ~ 45

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.

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

Journal of Cell Science ◽

10.1242/jcs.107.3.487 ◽

1994 ◽

Vol 107 (3) ◽

pp. 487-496 ◽

Cited By ~ 3

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.

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Insulin increases the Na(+)-K(+)-ATPase alpha 2-subunit in the surface of rat skeletal muscle: morphological evidence

AJP Cell Physiology ◽

10.1152/ajpcell.1993.265.6.c1716 ◽

1993 ◽

Vol 265 (6) ◽

pp. C1716-C1722 ◽

Cited By ~ 57

Author(s):

A. Marette ◽

J. Krischer ◽

L. Lavoie ◽

C. Ackerley ◽

J. L. Carpentier ◽

...

Keyword(s):

Skeletal Muscle ◽

Plasma Membrane ◽

Cellular Localization ◽

Protein A ◽

Morphological Evidence ◽

Mammalian Skeletal Muscle ◽

Tissue Fixation ◽

Insulin Stimulation ◽

Rat Skeletal Muscle ◽

Quantitative Evidence

The cellular localization of the alpha 2-subunit of the Na(+)-K(+)-ATPase was defined by immunoelectron microscopy, and the effect of insulin on the amount of alpha 2-immunoreactive subunits on the cell surface was quantitated. Two protocols were used for tissue fixation and immunolocalization. Protocol 1 was characterized by fixation with 2% paraformaldehyde, use of a monoclonal antibody, and detection with 3-nm-diameter gold-labeled Fab fragments or 10-nm gold-labeled immunoglobulin G. Protocol 2 was characterized by fixation with 4% paraformaldehyde plus 0.1% glutaraldehyde, use of a polyclonal antibody, and detection with 10-nm gold-labeled protein A. In control muscle, the alpha 2-subunit of the Na(+)-K(+)-ATPase was present at the plasma membrane and in intracellular tubular and vesicular structures located in subsarcolemmal and triadic regions. Acute insulin stimulation increased the number of immunolabeled alpha 2-subunits in the plasma membrane after both fixation protocols. The gain in the plasma membrane ranged from 1.5- to 3.7-fold and was significant at the level of P < 0.005. These results provide morphological quantitative evidence that the alpha 2-subunit of the Na(+)-K(+)-ATPase is present both at the plasma membrane and intracellularly in mammalian skeletal muscle and that insulin acutely increases its abundance in the muscle surface.

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Stimulation of glucose transport in skeletal muscle by hypoxia

Journal of Applied Physiology ◽

10.1152/jappl.1991.70.4.1593 ◽

1991 ◽

Vol 70 (4) ◽

pp. 1593-1600 ◽

Cited By ~ 203

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.

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Acute exercise increases the number of plasma membrane glucose transporters in rat skeletal muscle

FEBS Letters ◽

10.1016/0014-5793(88)80486-1 ◽

1988 ◽

Vol 238 (2) ◽

pp. 235-239 ◽

Cited By ~ 72

Author(s):

Michael F. Hirshman ◽

Harriet Wallberg-Henriksson ◽

Lawrence J. Wardzala ◽

Elizabeth D. Horton ◽

Edward S. Horton

Keyword(s):

Skeletal Muscle ◽

Plasma Membrane ◽

Acute Exercise ◽

Glucose Transporters ◽

Rat Skeletal Muscle

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

Canadian Journal of Zoology ◽

10.1139/z95-001 ◽

1995 ◽

Vol 73 (1) ◽

pp. 1-9 ◽

Cited By ~ 28

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.

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

Biochemical Journal ◽

10.1042/bj3210707 ◽

1997 ◽

Vol 321 (3) ◽

pp. 707-712 ◽

Cited By ~ 156

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.

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