Insulin Signaling and Glucose Transport in Insulin Resistant Skeletal Muscle

Author(s):  
Dana Galuska ◽  
Jeff Ryder ◽  
Yuichi Kawano ◽  
Maureen J. Charron ◽  
Juleen R. Zierath
2005 ◽  
Vol 288 (6) ◽  
pp. E1188-E1194 ◽  
Author(s):  
Betsy B. Dokken ◽  
Julie A. Sloniger ◽  
Erik J. Henriksen

Glycogen synthase kinase-3 (GSK3) has been implicated in the multifactorial etiology of skeletal muscle insulin resistance in animal models and in human type 2 diabetic subjects. However, the potential molecular mechanisms involved are not yet fully understood. Therefore, we determined if selective GSK3 inhibition in vitro leads to an improvement in insulin action on glucose transport activity in isolated skeletal muscle of insulin-resistant, prediabetic obese Zucker rats and if these effects of GSK3 inhibition are associated with enhanced insulin signaling. Type I soleus and type IIb epitrochlearis muscles from female obese Zucker rats were incubated in the absence or presence of a selective, small organic GSK3 inhibitor (1 μM CT118637, Ki < 10 nM for GSK3α and GSK3β). Maximal insulin stimulation (5 mU/ml) of glucose transport activity, glycogen synthase activity, and selected insulin-signaling factors [tyrosine phosphorylation of insulin receptor (IR) and IRS-1, IRS-1 associated with p85 subunit of phosphatidylinositol 3-kinase, and serine phosphorylation of Akt and GSK3] were assessed. GSK3 inhibition enhanced ( P <0.05) basal glycogen synthase activity and insulin-stimulated glucose transport in obese epitrochlearis (81 and 24%) and soleus (108 and 20%) muscles. GSK3 inhibition did not modify insulin-stimulated tyrosine phosphorylation of IR β-subunit in either muscle type. However, in obese soleus, GSK3 inhibition enhanced (all P < 0.05) insulin-stimulated IRS-1 tyrosine phosphorylation (45%), IRS-1-associated p85 (72%), Akt1/2 serine phosphorylation (30%), and GSK3β serine phosphorylation (39%). Substantially smaller GSK3 inhibitor-mediated enhancements of insulin action on these insulin signaling factors were observed in obese epitrochlearis. These results indicate that selective GSK3 inhibition enhances insulin action in insulin-resistant skeletal muscle of the prediabetic obese Zucker rat, at least in part by relieving the deleterious effects of GSK3 action on post-IR insulin signaling. These effects of GSK3 inhibition on insulin action are greater in type I muscle than in type IIb muscle from these insulin-resistant animals.


2009 ◽  
Vol 23 (S1) ◽  
Author(s):  
Antoni Ryszard Macko ◽  
Alan Beneze ◽  
Mary K. Teachey ◽  
Erik J. Henriksen

2004 ◽  
Vol 287 (3) ◽  
pp. E529-E536 ◽  
Author(s):  
Vitoon Saengsirisuwan ◽  
Felipe R. Perez ◽  
Julie A. Sloniger ◽  
Thomas Maier ◽  
Erik J. Henriksen

We have shown previously (Saengsirisuwan V, Kinnick TR, Schmit MB, and Henriksen EJ. J Appl Physiol 91: 145–153, 2001) that the antioxidant R-(+)-α-lipoic acid (R-ALA), combined with endurance exercise training (ET), increases glucose transport in insulin-resistant skeletal muscle in an additive fashion. The purpose of the present study was to investigate possible cellular mechanisms responsible for this interactive effect. We evaluated the effects of R-ALA alone, ET alone, or R-ALA and ET in combination on insulin-stimulated glucose transport, protein expression, and functionality of specific insulin-signaling factors in soleus muscle of obese Zucker ( fa/fa) rats. Obese animals remained sedentary, received R-ALA (30 mg·kg body wt−1·day−1), performed ET (daily treadmill running for ≤60 min), or underwent both R-ALA treatment and ET for 15 days. R-ALA or ET individually increased ( P < 0.05) insulin-mediated (5 mU/ml) glucose transport (2-deoxyglucose uptake) in soleus muscle by 45 and 68%, respectively, and this value was increased to the greatest extent (124%) in the combined treatment group. Soleus insulin receptor substrate (IRS)-1 protein was significantly increased by R-ALA alone (30%) or ET alone (31%), and a further enhancement (55%) was observed after the combination treatment in the obese animals. Enhanced levels of IRS-1 protein expression after individual or combined interventions were significantly correlated with insulin action on glucose transport activity ( r = 0.597, P = 0.0055). Similarly, insulin-mediated IRS-1 associated with the p85 regulatory subunit of phosphatidylinositol 3-kinase was increased by R-ALA (317%) and ET (319%) and to the greatest extent (435%) (all P < 0.05) by the combination treatment. These results indicate that the improvements of insulin action in insulin-resistant skeletal muscle after R-ALA or ET, alone and in combination, were associated with increases in IRS-1 protein expression and IRS-1 associated with p85.


Diabetes ◽  
1995 ◽  
Vol 44 (6) ◽  
pp. 695-698 ◽  
Author(s):  
J. L. Azevedo ◽  
J. O. Carey ◽  
W. J. Pories ◽  
P. G. Morris ◽  
G. L. Dohm

2003 ◽  
Vol 285 (1) ◽  
pp. E98-E105 ◽  
Author(s):  
Erik J. Henriksen ◽  
Mary K. Teachey ◽  
Zachary C. Taylor ◽  
Stephan Jacob ◽  
Arne Ptock ◽  
...  

The fatty acid-conjugated linoleic acid (CLA) enhances glucose tolerance and insulin action on skeletal muscle glucose transport in rodent models of insulin resistance. However, no study has directly compared the metabolic effects of the two primary CLA isomers, cis-9, trans-11-CLA (c9,t11-CLA) and trans-10, cis-12-CLA (t10,c12-CLA). Therefore, we assessed the effects of a 50:50 mixture of these two CLA isomers (M-CLA) and of preparations enriched in either c9,t11-CLA (76% enriched) or t10,c12-CLA (90% enriched) on glucose tolerance and insulin-stimulated glucose transport in skeletal muscle of the insulin-resistant obese Zucker ( fa/ fa) rat. Animals were treated daily by gavage with either vehicle (corn oil), M-CLA, c9,t11-CLA, or t10,c12-CLA (all CLA treatments at 1.5 g total CLA/kg body wt) for 21 consecutive days. During an oral glucose tolerance test, glucose responses were reduced ( P < 0.05) by 10 and 16%, respectively, in the M-CLA and t10,c12-CLA animals, respectively, whereas insulin responses were diminished by 21 and 19% in these same groups. There were no significant alterations in these responses in the c9,t11-CLA group. Insulin-mediated glucose transport activity was enhanced by M-CLA treatment in both type I soleus (32%) and type IIb epitrochlearis (58%) muscles and by 36 and 48%, respectively, with t10,c12-CLA. In the soleus, these increases were associated with decreases in protein carbonyls (index of oxidative stress, r = -0.616, P = 0.0038) and intramuscular triglycerides ( r = -0.631, P = 0.0028). Treatment with c9,t11-CLA was without effect on these variables. These results suggest that the ability of CLA treatment to improve glucose tolerance and insulin-stimulated glucose transport activity in insulin-resistant skeletal muscle of the obese Zucker rat are associated with a reduction in oxidative stress and muscle lipid levels and can be specifically ascribed to the actions of the t10,c12 isomer. In the obese Zucker rat, the c9,t11 isomer of CLA is metabolically neutral.


2013 ◽  
Vol 27 (S1) ◽  
Author(s):  
Paola Llanos ◽  
Ariel Contreras‐Ferrat ◽  
Cesár Osorio‐Fuentealba ◽  
Alejandra Espinosa ◽  
Jorge Hidalgo ◽  
...  

2002 ◽  
Vol 205 (23) ◽  
pp. 3739-3746 ◽  
Author(s):  
Naresh Kumar ◽  
Chinmoy S. Dey

SUMMARY Sulfonylurea drugs are used in the treatment of type 2 diabetes. The mechanism of action of sulfonylureas is to release insulin from pancreatic cells and they have been proposed to act on insulin-sensitive tissues to enhance glucose uptake. The goal of the present study was to test the hypothesis that gliclazide, a second-generation sulfonylurea, could enhance insulin signaling in insulin-resistant skeletal muscle cells. We demonstrated that gliclazide enhanced insulin-stimulated insulin receptor tyrosine phosphorylation in insulin-resistant skeletal muscle cells. Although insulin receptor substrate-1 tyrosine phosphorylation was unaffected by gliclazide treatment, phosphatidylinositol 3-kinase activity was partially restored by treatment with gliclazide. No increase in 2-deoxyglucose uptake in insulin-resistant cells by treatment with gliclazide was observed. Further investigations into the mitogen-activated protein kinase (MAPK) pathway revealed that insulin-stimulated p38 phosphorylation was impaired, as compared with extracellular-signal-regulated kinase (ERK) and c-Jun N-terminal kinase(JNK), which were phosphorylated normally in insulin-resistant cells. Treatment with gliclazide could not restore p38 phosphorylation in insulin-resistant cells. We propose that gliclazide can regulate part of the insulin signaling in insulin-resistant skeletal muscle, and p38 could be a potential therapeutic target for glucose uptake to treat insulin resistance.


1989 ◽  
Vol 257 (3) ◽  
pp. E418-E425 ◽  
Author(s):  
M. O. Sowell ◽  
S. L. Dutton ◽  
M. G. Buse

Denervation (24 h) of skeletal muscle causes severe postreceptor insulin resistance of glucose transport and glycogen synthesis that is demonstrable in isolated muscles after short (30 min) preincubations. After longer preincubations (2-4 h), the insulin response of glucose transport increased to normal, whereas glycogen synthesis remained insulin resistant. Basal and insulin-stimulated amino acid transport were significantly lower in denervated muscles than in controls after short or long incubations, although the percentage stimulation of transport by insulin was not significantly different. The development of glucose transport insulin resistance after denervation was not attributable to increased sensitivity to glucocorticoids or adenosine. The selective in vitro reversal of glucose transport insulin resistance was not dependent on medium composition, did not require protein or prostaglandin synthesis, and could not be attributed to release of a positive regulator into the medium. The data suggest 1) the insulin receptor in muscle stimulates glucose transport by a signaling pathway that is not shared by other insulin-sensitive effector systems, and 2) denervation may affect insulin receptor signal transduction at more than one site.


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