Clenbuterol prevents epinephrine from antagonizing insulin-stimulated muscle glucose uptake

2002 ◽  
Vol 92 (3) ◽  
pp. 1285-1292 ◽  
Author(s):  
Desmond G. Hunt ◽  
Zhenping Ding ◽  
John L. Ivy
Keyword(s):  
Glucose Uptake ◽  
Kinase Activity ◽  
Pi3 Kinase ◽  
Intracellular Concentration ◽  
Insulin Receptor Substrate ◽  
Phosphatidylinositol 3 Kinase ◽  
Rat Skeletal Muscle ◽  
Slow Twitch ◽  
Chronic Clenbuterol ◽  
Fast Twitch

In the present study, we investigated the effects of chronic clenbuterol treatment on insulin-stimulated glucose uptake in the presence of epinephrine in isolated rat skeletal muscle. Insulin (50 μU/ml) increased glucose uptake in both fast-twitch (epitrochlearis) and slow-twitch (soleus) muscles. In the presence of 24 nM epinephrine, insulin-stimulated glucose uptake was completely suppressed. This suppression of glucose uptake by epinephrine was accompanied by an increase in the intracellular concentration of glucose 6-phosphate and a decrease in insulin-receptor substrate-1-associated phosphatidylinositol 3-kinase (IRS-1/PI3-kinase) activity. Clenbuterol treatment had no direct effect on insulin-stimulated glucose uptake. However, after clenbuterol treatment, epinephrine was ineffective in attenuating insulin-stimulated muscle glucose uptake. This ineffectiveness of epinephrine to suppress insulin-stimulated glucose uptake occurred in conjunction with its inability to increase the intracellular concentration of glucose 6-phosphate and attenuate IRS-1/PI3-kinase activity. Results of this study indicate that the effectiveness of epinephrine to inhibit insulin-stimulated glucose uptake is severely diminished in muscle from rats pretreated with clenbuterol.

Propranolol prevents epinephrine from limiting insulin-stimulated muscle glucose uptake during contraction

2002 ◽  
Vol 93 (2) ◽  
pp. 697-704 ◽  
Author(s):  
Desmond G. Hunt ◽  
Zhenping Ding ◽  
John L. Ivy
Keyword(s):  
Insulin Receptor ◽  
Glucose Uptake ◽  
Kinase Activity ◽  
Pi3 Kinase ◽  
Insulin Receptor Substrate ◽  
Muscle Preparation ◽  
Acute Effects ◽  
Glucose Clearance ◽  
Slow Twitch ◽  
Isolated Rat

β-Blockade results in rapid glucose clearance and premature fatigue during exercise. To investigate the cause of this increased glucose clearance, we studied the acute effects of propranolol on insulin-stimulated muscle glucose uptake during contraction in the presence of epinephrine with an isolated rat muscle preparation. Glucose uptake increased in both fast- (epitrochlearis) and slow-twitch (soleus) muscle during insulin or contraction stimulation. In the presence of 24 nM epinephrine, glucose uptake during contraction was completely suppressed when insulin was present. This suppression of glucose uptake by epinephrine was accompanied by a decrease in insulin receptor substrate (IRS)-1-phosphatidylinositol 3 (PI3)-kinase activity. Propranolol had no direct effect on insulin-stimulated glucose uptake during contraction. However, epinephrine was ineffective in attenuating insulin-stimulated glucose uptake during contraction in the presence of propranolol. This ineffectiveness of epinephrine to suppress insulin-stimulated glucose uptake during contraction occurred in conjunction with its inability to completely suppress IRS-1-PI3-kinase activity. Results of this study indicate that the effectiveness of epinephrine to inhibit insulin-stimulated glucose uptake during contraction is severely diminished in muscle exposed to propranolol. Thus the increase in glucose clearance and premature fatigue associated with β-blockade could result from the inability of epinephrine to attenuate insulin-stimulated muscle glucose uptake.

scholarly journals Mechanisms for increased insulin-stimulated Akt phosphorylation and glucose uptake in fast- and slow-twitch skeletal muscles of calorie-restricted rats

2011 ◽  
Vol 300 (6) ◽  
pp. E966-E978 ◽  
Author(s):  
Naveen Sharma ◽  
Edward B. Arias ◽  
Abhijit D. Bhat ◽  
Donel A. Sequea ◽  
Steve Ho ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Insulin Dose ◽  
Heat Shock Protein 90 ◽  
Regulatory Proteins ◽  
Phosphatidylinositol 3 Kinase ◽  
Akt Phosphorylation ◽  
Pi3k Activity ◽  
Phosphatase 2A ◽  
Slow Twitch ◽  
Fast Twitch

Calorie restriction [CR; ∼65% of ad libitum (AL) intake] improves insulin-stimulated glucose uptake (GU) and Akt phosphorylation in skeletal muscle. We aimed to elucidate the effects of CR on 1) processes that regulate Akt phosphorylation [insulin receptor (IR) tyrosine phosphorylation, IR substrate 1-phosphatidylinositol 3-kinase (IRS-PI3K) activity, and Akt binding to regulatory proteins (heat shock protein 90, Appl1, protein phosphatase 2A)]; 2) Akt substrate of 160-kDa (AS160) phosphorylation on key phosphorylation sites; and 3) atypical PKC (aPKC) activity. Isolated epitrochlearis (fast-twitch) and soleus (slow-twitch) muscles from AL or CR (6 mo duration) 9-mo-old male F344BN rats were incubated with 0, 1.2, or 30 nM insulin and 2-deoxy-[3H]glucose. Some CR effects were independent of insulin dose or muscle type: CR caused activation of Akt (Thr308and Ser473) and GU in both muscles at both insulin doses without CR effects on IRS1-PI3K, Akt-PP2A, or Akt-Appl1. Several muscle- and insulin dose-specific CR effects were revealed. Akt-HSP90 binding was increased in the epitrochlearis; AS160 phosphorylation (Ser588and Thr642) was greater for CR epitrochlearis at 1.2 nM insulin; and IR phosphorylation and aPKC activity were greater for CR in both muscles with 30 nM insulin. On the basis of these data, our working hypothesis for improved insulin-stimulated GU with CR is as follows: 1) elevated Akt phosphorylation is fundamental, regardless of muscle or insulin dose; 2) altered Akt binding to regulatory proteins (HSP90 and unidentified Akt partners) is involved in the effects of CR on Akt phosphorylation; 3) Akt effects on GU depend on muscle- and insulin dose-specific elevation in phosphorylation of Akt substrates, including, but not limited to, AS160; and 4) greater IR phosphorylation and aPKC activity may contribute at higher insulin doses.

scholarly journals Insulin receptor substrate 1 is phosphorylated by the serine kinase activity of phosphatidylinositol 3-kinase

1994 ◽  
Vol 304 (1) ◽  
pp. 17-21 ◽  
Author(s):  
J F Tanti ◽  
T Grémeaux ◽  
E Van Obberghen ◽  
Y Le Marchand-Brustel
Keyword(s):  
Insulin Receptor ◽  
Kinase Activity ◽  
Pi3 Kinase ◽  
Serine Phosphorylation ◽  
Kinase Assay ◽  
Insulin Receptor Substrate ◽  
Phosphatidylinositol 3 Kinase ◽  
Serine Kinase ◽  
Phosphatidylinositol 3

Insulin receptor substrate (IRS) 1, which is tyrosine phosphorylated in response to insulin, presents multiple serine/threonine phosphorylation sites. To search for a serine kinase activity towards IRS 1, immunoprecipitates from basal or stimulated 3T3-L1 adipocytes were used in an in vitro kinase assay. When IRS 1 was isolated from insulin-treated cells, serine phosphorylation of IRS 1 occurred, which we attribute to the kinase activity of the phosphatidylinositol 3-kinase (PI3-kinase). Importantly, in an in vitro reconstitution assay, an excess of the PI3-kinase subunit prevents this phosphorylation. Together, our results suggest that following insulin stimulation, PI3-kinase associates with IRS 1, allowing for its serine phosphorylation. This phosphorylation event could play a role in the modulation of insulin signalling.

scholarly journals Epinephrine inhibits insulin-stimulated muscle glucose transport

2002 ◽  
Vol 93 (5) ◽  
pp. 1638-1643 ◽  
Author(s):  
Desmond G. Hunt ◽  
John L. Ivy
Keyword(s):  
Glucose Transport ◽  
Pi3 Kinase ◽  
Phosphatidylinositol 3 Kinase ◽  
Kinase Activation ◽  
Essential Step ◽  
Muscle Types ◽  
Slow Twitch ◽  
Muscle Glucose Transport ◽  
Fast Twitch ◽  
Epinephrine Concentration

We recently demonstrated that epinephrine could inhibit the activation by insulin of insulin receptor substrate-1 (IRS-1)-associated phosphatidylinositol 3-kinase (PI3-kinase) in skeletal muscle (Hunt DG, Zhenping D, and Ivy JL. J Appl Physiol 92: 1285–1292, 2002). Activation of PI3-kinase is recognized as an essential step in the activation of muscle glucose transport by insulin. We therefore investigated the effect of epinephrine on insulin-stimulated glucose transport in both fast-twitch (epitrochlearis) and slow-twitch (soleus) muscle of the rat by using an isolated muscle preparation. Glucose transport was significantly increased in the epitrochlearis and soleus when incubated in 50 and 100 μU/ml insulin, respectively. Activation of glucose transport by 50 μU/ml insulin was inhibited by 24 nM epinephrine in both muscle types. This inhibition of glucose transport by epinephrine was accompanied by suppression of IRS-1-associated PI3-kinase activation. However, when muscles were incubated in 100 μU/ml insulin, 24 nM epinephrine was unable to inhibit IRS-1-associated PI3-kinase activation or glucose transport. Even when epinephrine concentration was increased to 500 nM, no attenuating effect was observed on glucose transport. Results of this study indicate that epinephrine is capable of inhibiting glucose transport activated by a moderate, but not a high, physiological insulin concentration. The inhibition of glucose transport by epinephrine appears to involve the inhibition of IRS-1-associated PI3-kinase activation.

scholarly journals NF-κB-Inducing Kinase (NIK) Mediates Skeletal Muscle Insulin Resistance: Blockade by Adiponectin

Endocrinology ◽  
2011 ◽  
Vol 152 (10) ◽  
pp. 3622-3627 ◽  
Author(s):  
Sanjeev Choudhary ◽  
Sandeep Sinha ◽  
Yanhua Zhao ◽  
Srijita Banerjee ◽  
Padma Sathyanarayana ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Kinase Activity ◽  
Pi3 Kinase ◽  
Dominant Negative ◽  
Muscle Insulin Resistance ◽  
Akt Phosphorylation ◽  
Skeletal Muscle Insulin Resistance ◽  
Obese Subjects

Enhanced levels of nuclear factor (NF)-κB-inducing kinase (NIK), an upstream kinase in the NF-κB pathway, have been implicated in the pathogenesis of chronic inflammation in diabetes. We investigated whether increased levels of NIK could induce skeletal muscle insulin resistance. Six obese subjects with metabolic syndrome underwent skeletal muscle biopsies before and six months after gastric bypass surgery to quantitate NIK protein levels. L6 skeletal myotubes, transfected with NIK wild-type or NIK kinase-dead dominant negative plasmids, were treated with insulin alone or with adiponectin and insulin. Effects of NIK overexpression on insulin-stimulated glucose uptake were estimated using tritiated 2-deoxyglucose uptake. NF-κB activation (EMSA), phosphatidylinositol 3 (PI3) kinase activity, and phosphorylation of inhibitor κB kinase β and serine-threonine kinase (Akt) were measured. After weight loss, skeletal muscle NIK protein was significantly reduced in association with increased plasma adiponectin and enhanced AMP kinase phosphorylation and insulin sensitivity in obese subjects. Enhanced NIK expression in cultured L6 myotubes induced a dose-dependent decrease in insulin-stimulated glucose uptake. The decrease in insulin-stimulated glucose uptake was associated with a significant decrease in PI3 kinase activity and protein kinase B/Akt phosphorylation. Overexpression of NIK kinase-dead dominant negative did not affect insulin-stimulated glucose uptake. Adiponectin treatment inhibited NIK-induced NF-κB activation and restored insulin sensitivity by restoring PI3 kinase activation and subsequent Akt phosphorylation. These results indicate that NIK induces insulin resistance and further indicate that adiponectin exerts its insulin-sensitizing effect by suppressing NIK-induced skeletal muscle inflammation. These observations suggest that NIK could be an important therapeutic target for the treatment of insulin resistance associated with inflammation in obesity and type 2 diabetes.

Glucose uptake and metabolic stress in rat muscles stimulated electrically with different protocols

2001 ◽  
Vol 91 (3) ◽  
pp. 1237-1244 ◽  
Author(s):  
Rune Aslesen ◽  
Ellen M. L. Engebretsen ◽  
Jesper Franch ◽  
Jørgen Jensen
Keyword(s):  
Glucose Uptake ◽  
Wistar Rats ◽  
Metabolic Stress ◽  
Reduction In Force ◽  
Tracer Amount ◽  
Slow Twitch ◽  
Fast Twitch ◽  
The Relationship ◽  
Glycogen Breakdown

In the present study, the relationship between the pattern of electrical stimulation and glucose uptake was investigated in slow-twitch muscles (soleus) and fast-twitch muscles (epitrochlearis) from Wistar rats. Muscles were stimulated electrically for 30 min in vitro with either single pulses (frequencies varied between 0.8 and 15 Hz) or with 200-ms trains (0.1–2 Hz). Glucose uptake (measured with tracer amount of 2-[3H]deoxyglucose) increased with increasing number of impulses whether delivered as single pulses or as short trains. The highest glucose uptake achieved with short tetanic contractions was similar in soleus and epitrochlearis (10.9 ± 0.7 and 12.0 ± 0.8 mmol · kg dry wt−1 · 30 min−1, respectively). Single pulses, on the other hand, increased contraction-stimulated glucose uptake less in soleus than in epitrochlearis (7.5 ± 1.1 and 11.7 ± 0.5 mmol · kg dry wt−1 · 30 min−1, respectively; P < 0.02). Glucose uptake correlated with glycogen breakdown in soleus ( r = 0.84, P < 0.0001) and (epitrochlearis: r = 0.91, P < 0.0001). Contraction-stimulated glucose uptake also correlated with breakdown of ATP and PCr and with reduction in force. Our data suggest that metabolic stress mediates contraction-stimulated glucose uptake.

Diazepam reveals different rate-limiting processes in rat skeletal muscle contraction

1987 ◽  
Vol 65 (2) ◽  
pp. 272-273 ◽  
Author(s):  
Michael Chua ◽  
Angela F. Dulhunty
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Calcium Binding ◽  
Extensor Digitorum Longus ◽  
Calcium Uptake ◽  
Rat Skeletal Muscle ◽  
Skeletal Muscle Contraction ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Rate Limiting

The action of the tranquilizer diazepam on rat skeletal muscle showed that relaxation of isometric twitches is controlled by different processes in extensor digitorum longus (fast-twitch) and soleus (slow-twitch) muscles. Diazepam caused an increase in the amplitude of twitches in fibres from both muscles but increased the twitch duration only in soleus. The amplitude of fused tetani were reduced in both muscles and the rate of relaxation after the tetanus slowed by as much as 34% when the amplitude of the tetanus was reduced by only 11%. The slower tetanic relaxation indicated that calcium uptake by the sarcoplasmic reticulum was slower than normal in slow- and fast-twitch fibres. We conclude therefore that calcium uptake by the sarcoplasmic reticulum is rate limiting for twitch relaxation in slow-twitch but not fast-twitch fibres and suggest that calcium binding to parvalbumin controls relaxation in the fast fibres.

scholarly journals Phosphatidylinositol 3-kinase acts at an intracellular membrane site to enhance GLUT4 exocytosis in 3T3-L1 cells

1996 ◽  
Vol 313 (1) ◽  
pp. 125-131 ◽  
Author(s):  
Jing YANG ◽  
James F. CLARKE ◽  
Catriona J. ESTER ◽  
Paul W. YOUNG ◽  
Masato KASUGA ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Insulin Receptor ◽  
Time Course ◽  
Glucose Transporter ◽  
Kinase Activity ◽  
Insulin Receptor Substrate ◽  
Low Density ◽  
Intracellular Membrane ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatidylinositol 3

Glucose transporters (GLUTs) are continuously recycled in 3T3-L1 cells and so insulin, through its action on phosphatidylinositol 3-kinase (PI 3-kinase), could potentially alter the distribution of these transporters by enhancing retention in the plasma membrane or acting intracellularly to increase exocytosis, either by stimulating a budding or a docking and fusion process. To examine the site of involvement of PI 3-kinase in the glucose transporter recycling pathway, we have determined the kinetics of recycling under conditions in which the PI 3-kinase activity is inhibited by wortmannin. Wortmannin addition to fully insulin-stimulated cells induces a net reduction of glucose transport activity with a time course that is consistent with a major effect on the return of internalized transporters to the plasma membrane. The exocytosis of GLUT1 and GLUT4 is reduced to very low levels in wortmannin-treated cells (≈ 0.009 min-1), but the endocytosis of these isoforms is not markedly perturbed and the rate constants are approx. 10-fold higher than for exocytosis (0.099 and 0.165 min-1, respectively). The slow reduction in basal activity following treatment with wortmannin is consistent with a wortmannin effect on constitutive recycling as well as insulin-regulated exocytosis. PI 3-kinase activity that is precipitated by anti-phosphotyrosine, anti-[insulin receptor substrate 1 (IRS1)] and anti-α-p85 antibodies show the same level of insulin-stimulated activity, ≈ 0.5 pmol/20 min per dish of 3T3-L1 cells. Since the activities precipitated by all three antibodies are similar, it seems unlikely that a second insulin receptor substrate, IRS2, contributes significantly to the insulin signalling observed in 3T3-L1 cells. To examine whether insulin targets PI 3-kinase to intracellular membranes we have carried out subcellular fractionation studies. These suggest that nearly all the insulin-stimulated PI 3-kinase activity is located on intracellular, low-density, membranes. In addition, the association of PI 3-kinase with IRS1 appears to partially deplete the cytoplasm of α-p85-precipitatable activity, suggesting that IRS1 may redistribute PI 3-kinase from the cytoplasm to the low-density microsome membranes. Taken together, the trafficking kinetic and PI 3-kinase distribution studies suggest an intracellular membrane site of action of the enzyme in enhancing glucose transporter exocytosis.

Sign in / Sign up

Export Citation Format

Share Document