Role of Transverse Tubules (T-Tubules) in Muscle Glucose Transport

1998 ◽  
pp. 27-34 ◽  
Author(s):  
G. Lynis Dohm ◽  
Ronald W. Dudek
Keyword(s):  
Glucose Transport ◽  
Transverse Tubules ◽  
T Tubules ◽  
Muscle Glucose Transport

Role of transverse tubules in insulin stimulated muscle glucose transport

1993 ◽  
Vol 52 (1) ◽  
pp. 1-7 ◽  
Author(s):  
G. Lynis Dohm ◽  
Patricia L. Dolan ◽  
Wilhelm R. Frisell ◽  
Ronald W. Dudek
Keyword(s):  
Glucose Transport ◽  
Transverse Tubules ◽  
Muscle Glucose Transport

scholarly journals Glucose-dependent insulinotropic polypeptide directly induces glucose transport in rat skeletal muscle

2015 ◽  
Vol 309 (3) ◽  
pp. R295-R303 ◽  
Author(s):  
Laelie A. Snook ◽  
Emery M. Nelson ◽  
David J. Dyck ◽  
David C. Wright ◽  
Graham P. Holloway
Keyword(s):  
Skeletal Muscle ◽  
Glucose Transport ◽  
Soleus Muscle ◽  
Serum Insulin ◽  
Current Data ◽  
Signaling Mechanism ◽  
Akt Phosphorylation ◽  
Glucose Challenge ◽  
Muscle Glucose Transport

Several gastrointestinal proteins have been identified to have insulinotropic effects, including glucose-dependent insulinotropic polypeptide (GIP); however, the direct effects of incretins on skeletal muscle glucose transport remain largely unknown. Therefore, the purpose of the current study was to examine the role of GIP on skeletal muscle glucose transport and insulin signaling in rats. Relative to a glucose challenge, a mixed glucose+lipid oral challenge increased circulating GIP concentrations, skeletal muscle Akt phosphorylation, and improved glucose clearance by ∼35% ( P < 0.05). These responses occurred without alterations in serum insulin concentrations. In an incubated soleus muscle preparation, GIP directly stimulated glucose transport and increased GLUT4 accumulation on the plasma membrane in the absence of insulin. Moreover, the ability of GIP to stimulate glucose transport was mitigated by the addition of the PI 3-kinase (PI3K) inhibitor wortmannin, suggesting that signaling through PI3K is required for these responses. We also provide evidence that the combined stimulatory effects of GIP and insulin on soleus muscle glucose transport are additive. However, the specific GIP receptor antagonist (Pro3)GIP did not attenuate GIP-stimulated glucose transport, suggesting that GIP is not signaling through its classical receptor. Together, the current data provide evidence that GIP regulates skeletal muscle glucose transport; however, the exact signaling mechanism(s) remain unknown.

scholarly journals Mechanism of hypoxia-stimulated glucose transport in rat skeletal muscle: potential role of glycogen

1998 ◽  
Vol 274 (5) ◽  
pp. E773-E778 ◽  
Author(s):  
Thomas H. Reynolds ◽  
Joseph T. Brozinick ◽  
M. A. Rogers ◽  
Samuel W. Cushman
Keyword(s):  
Exercise Training ◽  
Glucose Transport ◽  
Potential Role ◽  
Transport Activity ◽  
Glut 4 ◽  
Selective Targeting ◽  
Transport Response ◽  
Muscle Glucose Transport ◽  
Strong Inverse Relationship

We have previously reported that exercise training is associated with enhanced insulin-stimulated glucose transport activity and inhibited hypoxia-stimulated glucose transport activity in rat epitrochlearis muscle. Here we examine the potential role of muscle glycogen in the inhibited glucose transport response to hypoxia. Three days of swim training (2 × 3 h/day) produce a 100% increase in glycogen and a 70% increase in GLUT-4 in epitrochlearis muscle. Glucose transport after 1 h of hypoxia in muscles from fed exercise-trained (ET) rats is not significantly elevated above basal and is 40% lower than that in muscles from fed sedentary (SED) rats. Glycogen levels after 1 h of hypoxia are reduced by 27 and 64% in muscles from fed ET and fed SED rats, respectively. After 2 h of hypoxia, glucose transport is significantly increased above basal in muscles from fed ET rats, but this response is still 55% lower than that in muscles from fed SED rats. After 2 h of hypoxia, glycogen is reduced by 50 and 83% in muscles from fed ET and fed SED rats, respectively. After a modified overnight fast (≈4.5 g of chow), the glucose transport and glycogen responses to 1 h of hypoxia are not significantly different between muscles from ET and SED rats. These findings demonstrate a strong inverse relationship between glycogen and hypoxia-stimulated glucose transport activity and that high levels of glycogen contribute to the inhibited glucose transport response to hypoxia. Furthermore, failure of the overexpression of GLUT-4 after exercise training to enhance the glucose transport response to contraction/hypoxia suggests selective targeting of the additional GLUT-4 to the insulin-responsive pool.

Role of the AMPKγ3 isoform in hypoxia-stimulated glucose transport in glycolytic skeletal muscle

2009 ◽  
Vol 297 (6) ◽  
pp. E1388-E1394 ◽  
Author(s):  
Atul S. Deshmukh ◽  
Stephan Glund ◽  
Robby Z. Tom ◽  
Juleen R. Zierath
Keyword(s):  
Skeletal Muscle ◽  
Glucose Transport ◽  
Competitive Inhibitor ◽  
Energy Status ◽  
Wild Type ◽  
Ampk Activity ◽  
Energy Sensing ◽  
Edl Muscle ◽  
Muscle Glucose Transport

Skeletal muscle glucose transport is regulated via the canonical insulin-signaling cascade as well as by energy-sensing signals. 5′-AMP-activated protein kinase (AMPK) has been implicated in the energy status regulation of glucose transport. We determined the role of the AMPKγ3 isoform in hypoxia-mediated energy status signaling and glucose transport in fast-twitch glycolytic extensor digitorum longus (EDL) muscle from AMPKγ3-knockout (KO) mice and wild-type mice. Although hypoxia increased glucose transport ( P < 0.001) in wild-type mice, this effect was attenuated in AMPKγ3-KO mice (45% reduction, P < 0.01). The role of Ca2+-mediated signaling was tested using the Ca2+/calmodulin competitive inhibitor KN-93. KN-93 exposure reduced hypoxia-mediated glucose transport in AMPKγ3-KO and wild-type mice ( P < 0.05). To further explore the underlying signaling mechanisms, phosphorylation of CaMKII, AMPK, ACC, and TBC1D1/D4 as well as isoform-specific AMPK activity was determined. Basal and hypoxia-mediated phosphorylation of CaMKII, AMPK, and ACC as well as α1- and α2-associated AMPK activity was comparable between AMPKγ3-KO and wild-type mice. KN-93 reduced hypoxia-mediated CaMKII phosphorylation in AMPKγ3-KO and wild-type mice ( P < 0.05), whereas phosphorylation of AMPK and ACC as well as α1- and α2-associated AMPK activity was unaltered. Hypoxia increased TBC1D1/D4 phosphorylation in AMPKγ3-KO and wild-type mice ( P < 0.001). KN-93 exposure prevented this effect in AMPKγ3-KO, but not in wild-type mice. Taken together, we provide direct evidence for a role of the AMPKγ3 isoform in hypoxia-mediated glucose transport in glycolytic muscle. Moreover, hypoxia-mediated TBC1D1/D4 phosphorylation was uncoupled from glucose transport in AMPKγ3-KO mice, indicating that TBC1D1/D4-independent mechanisms contribute to glucose transport in skeletal muscle.

Essential role of p38 MAPK for activation of skeletal muscle glucose transport by lithium

2007 ◽  
Vol 113 (4-5) ◽  
pp. 221-227 ◽  
Author(s):  
Nicholas B. Harrell ◽  
Mary K. Teachey ◽  
Nancy J. Gifford ◽  
Erik J. Henriksen
Keyword(s):  
Skeletal Muscle ◽  
Glucose Transport ◽  
P38 Mapk ◽  
Essential Role ◽  
Muscle Glucose Transport

Modulation of glucose transport in skeletal muscle by reactive oxygen species

2007 ◽  
Vol 102 (4) ◽  
pp. 1671-1676 ◽  
Author(s):  
Abram Katz
Keyword(s):  
Reactive Oxygen Species ◽  
Skeletal Muscle ◽  
Glucose Transport ◽  
Reactive Oxygen ◽  
Convincing Evidence ◽  
Oxygen Species ◽  
Carbohydrate Utilization ◽  
Muscle Glucose Transport ◽  
Amp Activated Protein Kinase

Glucose transport is an essential physiological process that is characteristic of all eukaryotic cells, including skeletal muscle. In skeletal muscle, glucose transport is mediated by the GLUT-4 protein under conditions of increased carbohydrate utilization. The three major physiological stimuli of glucose transport in muscle are insulin, exercise/contraction, and hypoxia. Here, the role of reactive oxygen species (ROS) in modulating glucose transport in skeletal muscle is reviewed. Convincing evidence for ROS involvement in insulin- and hypoxia-mediated transport in muscle is lacking. Recent experiments, based on pharmacological and genetic approaches, support a role for ROS in contraction-mediated glucose transport. During contraction, endogenously produced ROS appear to mediate their effects on glucose transport via AMP-activated protein kinase.

Insulin resistance of muscle glucose transport in rats fed a high-fat diet: a reevaluation

Diabetes ◽  
1997 ◽  
Vol 46 (11) ◽  
pp. 1761-1767 ◽  
Author(s):  
D. H. Han ◽  
P. A. Hansen ◽  
H. H. Host ◽  
J. O. Holloszy
Keyword(s):  
Insulin Resistance ◽  
Glucose Transport ◽  
High Fat Diet ◽  
High Fat ◽  
Muscle Glucose Transport

Antihypertensive Agent Moxonidine Enhances Muscle Glucose Transport in Insulin-Resistant Rats

Hypertension ◽  
1997 ◽  
Vol 30 (6) ◽  
pp. 1560-1565 ◽  
Author(s):  
Erik J. Henriksen ◽  
Stephan Jacob ◽  
Donovan L. Fogt ◽  
Erik B. Youngblood ◽  
Jochen Gödicke
Keyword(s):  
Glucose Transport ◽  
Antihypertensive Agent ◽  
Insulin Resistant ◽  
Muscle Glucose Transport
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