AMP-activated protein kinase activity and glucose uptake in rat skeletal muscle

2001 ◽  
Vol 280 (5) ◽  
pp. E677-E684 ◽  
Author(s):  
Nicolas Musi ◽  
Tatsuya Hayashi ◽  
Nobuharu Fujii ◽  
Michael F. Hirshman ◽  
Lee A. Witters ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Glucose Uptake ◽  
Muscle Contractions ◽  
Treadmill Running ◽  
Dependent Manner ◽  
Rat Skeletal Muscle ◽  
Amp Activated Protein Kinase ◽  
Dose Dependent

The AMP-activated protein kinase (AMPK) has been hypothesized to mediate contraction and 5-aminoimidazole-4-carboxamide 1-β-d-ribonucleoside (AICAR)-induced increases in glucose uptake in skeletal muscle. The purpose of the current study was to determine whether treadmill exercise and isolated muscle contractions in rat skeletal muscle increase the activity of the AMPKα1 and AMPKα2 catalytic subunits in a dose-dependent manner and to evaluate the effects of the putative AMPK inhibitors adenine 9-β-d-arabinofuranoside (ara-A), 8-bromo-AMP, and iodotubercidin on AMPK activity and 3- O-methyl-d-glucose (3-MG) uptake. There were dose-dependent increases in AMPKα2 activity and 3-MG uptake in rat epitrochlearis muscles with treadmill running exercise but no effect of exercise on AMPKα1 activity. Tetanic contractions of isolated epitrochlearis muscles in vitro significantly increased the activity of both AMPK isoforms in a dose-dependent manner and at a similar rate compared with increases in 3-MG uptake. In isolated muscles, the putative AMPK inhibitors ara-A, 8-bromo-AMP, and iodotubercidin fully inhibited AICAR-stimulated AMPKα2 activity and 3-MG uptake but had little effect on AMPKα1 activity. In contrast, these compounds had absent or minimal effects on contraction-stimulated AMPKα1 and -α2 activity and 3-MG uptake. Although the AMPKα1 and -α2 isoforms are activated during tetanic muscle contractions in vitro, in fast-glycolytic fibers, the activation of AMPKα2-containing complexes may be more important in regulating exercise-mediated skeletal muscle metabolism in vivo. Development of new compounds will be required to study contraction regulation of AMPK by pharmacological inhibition.

Possible involvement of the α1 isoform of 5′AMP-activated protein kinase in oxidative stress-stimulated glucose transport in skeletal muscle

2004 ◽  
Vol 287 (1) ◽  
pp. E166-E173 ◽  
Author(s):  
Taro Toyoda ◽  
Tatsuya Hayashi ◽  
Licht Miyamoto ◽  
Shin Yonemitsu ◽  
Masako Nakano ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Skeletal Muscle ◽  
Protein Kinase ◽  
Glucose Transport ◽  
Activation Process ◽  
Dependent Manner ◽  
Upstream Kinase ◽  
Metabolic Stresses ◽  
Amp Activated Protein Kinase

Recent studies have suggested that 5′AMP-activated protein kinase (AMPK) is activated in response to metabolic stresses, such as contraction, hypoxia, and the inhibition of oxidative phosphorylation, which leads to insulin-independent glucose transport in skeletal muscle. In the present study, we hypothesized that acute oxidative stress increases the rate of glucose transport via an AMPK-mediated mechanism. When rat epitrochlearis muscles were isolated and incubated in vitro in Krebs buffer containing the oxidative agent H2O2, AMPKα1 activity increased in a time- and dose-dependent manner, whereas AMPKα2 activity remained unchanged. The activation of AMPKα1 was associated with phosphorylation of AMPK Thr172, suggesting that an upstream kinase is involved in the activation process. H2O2-induced AMPKα1 activation was blocked in the presence of the antioxidant N-acetyl-l-cysteine (NAC), and H2O2 significantly increased the ratio of oxidized glutathione to glutathione (GSSG/GSH) concentrations, a sensitive marker of oxidative stress. H2O2 did not cause an increase in the conventional parameters of AMPK activation, such as AMP and AMP/ATP. H2O2 increased 3- O-methyl-d-glucose transport, and this increase was partially, but significantly, blocked in the presence of NAC. Results were similar when the muscles were incubated in a superoxide-generating system using hypoxanthine and xanthine oxidase. Taken together, our data suggest that acute oxidative stress activates AMPKα1 in skeletal muscle via an AMP-independent mechanism and leads to an increase in the rate of glucose transport, at least in part, via an AMPKα1-mediated mechanism.

PIKfyve: a new fish in the growing pool of AMPK substrates

2013 ◽  
Vol 455 (2) ◽  
pp. e1-e3
Author(s):  
James S. V. Lally ◽  
Gregory R. Steinberg
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Glucose Uptake ◽  
Muscle Contractions ◽  
Whole Body ◽  
Glucose Homoeostasis ◽  
Increase Glucose Uptake ◽  
Biochemical Journal ◽  
Complex Events ◽  
Amp Activated Protein Kinase

Skeletal muscle is critical for whole-body glucose homoeostasis. Insulin and muscle contractions induced by exercise can increase glucose uptake through distinct intracellular signalling pathways involving PKB (protein kinase B)/Akt and AMPK (AMP-activated protein kinase) respectively. Whereas the proximal events governing these processes are becoming well understood, less is known about the regulation of the complex events necessary for the control of glucose uptake at the plasma membrane. In recent years, a number of common targets of AMPK and PKB/Akt have emerged as important components controlling glucose uptake, but the necessary phosphorylation events required for the control of glucose uptake have remained more elusive. In the current issue of the Biochemical Journal, Liu et al. identify that PIKfyve, a phosphoinositide phosphate kinase, is required for contraction-stimulated glucose uptake. They demonstrate that AMPK directly phosphorylates PIKfyve at Ser307, the same site as PKB/Akt, and that phosphorylation is increased in response to muscle contractions. These data provide compelling evidence for a new AMPK substrate that converges with PKB/Akt signalling and may be critical for the control of glucose uptake in skeletal muscle.

scholarly journals Muscle contractions, AICAR, and insulin cause phosphorylation of an AMPK-related kinase

2005 ◽  
Vol 289 (6) ◽  
pp. E986-E992 ◽  
Author(s):  
Jonathan S. Fisher ◽  
Jeong-Sun Ju ◽  
Peter J. Oppelt ◽  
Jill L. Smith ◽  
Atsushi Suzuki ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Protein Kinase B ◽  
Cross Reactivity ◽  
Muscle Contractions ◽  
Rt Pcr ◽  
Rat Skeletal Muscle ◽  
Apparent Increase ◽  
A Site ◽  
Amp Activated Protein Kinase

We hypothesized that AMP-activated protein kinase-related kinase 5 (ARK5)/novel kinase family 1 (NUAK1), an AMP-activated protein kinase (AMPK)-related kinase that has been found to be stimulated by protein kinase B (Akt), would be expressed in rat skeletal muscle and activated by electrically elicited contractions, 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR), or insulin. We verified expression of ARK5 in muscle through RT-PCR and Western blot. Cross-reactivity of ARK5 immunoprecipitates with antibodies against phospho-AMPK was increased by ∼30% by muscle contractions and ∼60% by incubation of muscle with AICAR. AMPK was not detected in the ARK5 immunoprecipitates. Despite the apparent increase in phosphorylation of ARK5 at a site essential to its activation, neither contractions nor AICAR increased ARK5 activity. For muscles from animals injected with saline or insulin, we probed nonimmunoprecipitated samples in sequence for phosphotyrosine (P-Tyr), ARK5, and phosphorylated substrates of Akt (P-AS) and found that the ARK5 band could be precisely superimposed on phosphoprotein bands from the P-Tyr and P-AS blots. In the band corresponding to ARK5, insulin increased P-Tyr content by ∼45% and cross-reactivity with the antibody against P-AS by approximately threefold. We also detected ARK5 in phosphotyrosine immunoprecipitates. Our data suggest that increased phosphorylation of ARK5 by muscle contractions or exposure to AICAR is insufficient to activate ARK5 in skeletal muscle, suggesting that some other modification (e.g., phosphorylation on tyrosine or by Akt) may be necessary to its activity in muscle.

Effect of a β3-adrenergic agonist, BRL35135A, on glucose uptake in rat skeletal muscle in vivo and in vitro

1993 ◽  
Vol 139 (3) ◽  
pp. 479-486 ◽  
Author(s):  
H. Abe ◽  
Y. Minokoshi ◽  
T. Shimazu
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Plasma Concentration ◽  
Glucose Uptake ◽  
Dependent Manner ◽  
Peripheral Tissues ◽  
Brown Adipose ◽  
Dose Dependent

ABSTRACT The effects of the β3-agonist, BRL35135A, on glucose uptake in the peripheral tissues of the rat, including skeletal muscle, were studied using the 2-[3H]deoxyglucose method in anaesthetized adult animals. Intravenous infusion of the β3-agonist dose-dependently increased the rate constant of glucose uptake in three types of skeletal muscle, brown adipose tissue, white adipose tissue, heart and diaphragm, but not in the brain, spleen or lung. Although infusion of the β3-agonist did not change the plasma concentration of glucose appreciably, it caused an increase in the plasma concentration of insulin when given at more than 25 μg/kg per h. To ascertain whether the effect of the β3-agonist on glucose uptake in skeletal muscle is mediated by insulin, glucose uptake into soleus muscle isolated from young rats was also measured in vitro using different concentrations of the β3-agonist. The β3-agonist BRL37344 (an active metabolite of BRL35135A) significantly increased glucose transport in a dose-dependent manner, with maximum stimulation at 100 pmol/l. These results demonstrate that glucose uptake in skeletal muscle can be enhanced independently of the action of insulin, probably through the mediation of β3-adrenoceptors present in the tissue. Journal of Endocrinology (1993) 139, 479–486

A possible role for AMP-activated protein kinase in exercise-induced glucose utilization: insights from humans and transgenic animals

2003 ◽  
Vol 31 (1) ◽  
pp. 186-190 ◽  
Author(s):  
J.N. Nielsen ◽  
S.B. Jørgensen ◽  
C. Frøsig ◽  
B. Viollet ◽  
F. Andreelli ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Glucose Uptake ◽  
Glucose Transport ◽  
Transgenic Animals ◽  
Conclusive Evidence ◽  
Exercise Induced ◽  
Tight Correlation ◽  
Amp Activated Protein Kinase

Exercise-induced glucose uptake in skeletal muscle is mediated by an insulin-independent mechanism, but the actual signals to glucose transport in response to muscle contraction have not been identified. The 5´-AMP-activated protein kinase (AMPK) has emerged as a putative mediator of contraction-induced glucose transport, although no conclusive evidence has been provided so far. Recent experiments in AMPK transgenic mice suggest that glucose transport induced by 5-amino-4-imidazolecarboxamide riboside (AICAR) or hypoxia is mediated by AMPK. In contrast, contraction-induced glucose transport in rodent skeletal muscle induced by electrical stimulation in vitro or in situ is not influenced or is only partially reduced by abolishing both or one of the catalytic AMPK subunits. This is compatible with exercise studies done in humans, where no tight correlation is found between AMPK activity and glucose uptake during exercise. Taken together, these results question an essential role of AMPK in exercise-induced glucose uptake and imply that one or more additional pathways are involved in mediating glucose transport in skeletal muscle during exercise.

UCP-3 expression in skeletal muscle: effects of exercise, hypoxia, and AMP-activated protein kinase

2000 ◽  
Vol 279 (3) ◽  
pp. E622-E629 ◽  
Author(s):  
Min Zhou ◽  
Bao-Zhen Lin ◽  
Sean Coughlin ◽  
Gino Vallega ◽  
Paul F. Pilch
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Uncoupling Protein ◽  
Fold Increase ◽  
Treadmill Running ◽  
Mitochondrial Transporter ◽  
Edl Muscle ◽  
Amp Activated Protein Kinase ◽  
Carnitine Palmitoyltransferase 1

Uncoupling protein 3 (UCP-3), a member of the mitochondrial transporter superfamily, is expressed primarily in skeletal muscle where it may play a role in altering metabolic function under conditions of fuel depletion caused, for example, by fasting and exercise. Here, we show that treadmill running by rats rapidly (30 min) induces skeletal muscle UCP-3 mRNA expression (sevenfold after 200 min), as do hypoxia and swimming in a comparably rapid and substantial fashion. The expression of the mitochondrial transporters, carnitine palmitoyltransferase 1 and the tricarboxylate carrier, is unaffected under these conditions. Hypoxia and exercise-mediated induction of UCP-3 mRNA result in a corresponding four- to sixfold increase in rat UCP-3 protein. We treated extensor digitorum longus (EDL) muscle with 5′-amino-4-imidazolecarboxamide ribonucleoside (AICAR), a compound that activates AMP-activated protein kinase (AMPK), an enzyme known to be stimulated during exercise and hypoxia. Incubation of rat EDL muscle in vitro for 30 min with 2 mM AICAR causes a threefold increase in UCP-3 mRNA and a 1.5-fold increase of UCP-3 protein compared with untreated muscle. These data are consistent with the notion that activation of AMPK, presumably as a result of fuel depletion, rapidly regulates UCP-3 gene expression.

CaMKK is an upstream signal of AMP-activated protein kinase in regulation of substrate metabolism in contracting skeletal muscle

2009 ◽  
Vol 297 (6) ◽  
pp. R1724-R1732 ◽  
Author(s):  
Marcia J. Abbott ◽  
Arthur M. Edelman ◽  
Lorraine P. Turcotte
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Muscle Contraction ◽  
Glucose Uptake ◽  
Protein Content ◽  
Moderate Intensity ◽  
Dependent Manner ◽  
Substrate Metabolism ◽  
Caffeine Treatment ◽  
Amp Activated Protein Kinase

Multiple signals have been shown to be involved in regulation of fatty acid (FA) and glucose metabolism in contracting skeletal muscle. This study aimed to determine whether a Ca2+-stimulated kinase, CaMKK, is involved in regulation of contraction-induced substrate metabolism and whether it does so in an AMP-activated protein kinase (AMPK)-dependent manner. Rat hindlimbs were perfused at rest ( n = 16), with 3 mM caffeine ( n = 15), with 2 mM 5-aminoimidazole-4-carboxamide 1-β-d-ribofuranoside (AICAR; n = 16), or during moderate-intensity muscle contraction (MC; n = 14) and with or without 5 μM STO-609, a CaMKK inhibitor. FA uptake and oxidation increased ( P < 0.05) 64% and 71% by caffeine, 42% and 93% by AICAR, and 65% and 143% by MC. STO-609 abolished ( P < 0.05) caffeine- and MC-induced FA uptake and oxidation but had no effect with AICAR treatment. Glucose uptake increased ( P < 0.05) 104% by caffeine, 85% by AICAR, and 130% by MC, and STO-609 prevented the increase in glucose uptake in caffeine and muscle contraction groups. CaMKKβ activity increased ( P < 0.05) 113% by caffeine treatment and 145% by MC but was not affected by AICAR treatment. STO-609 prevented the caffeine- and MC-induced increase in CaMKKβ activity. Caffeine, AICAR, and MC increased ( P < 0.05) AMPKα2 activity by 295%, 11-fold, and 7-fold but did not affect AMPKα1 activity. STO-609 decreased ( P < 0.05) AMPKα2 activity induced by caffeine treatment and MC by 60% and 61% but did not affect AICAR-induced activity. Plasma membrane transport protein content of CD36 and glucose transporter 4 (GLUT4) increased ( P < 0.05) with caffeine, AICAR, and MC, and STO-609 prevented caffeine- and MC-induced increases in protein content. These results show the importance of Ca2+-dependent signaling via CaMKK activation in the regulation of substrate uptake and FA oxidation in contracting rat skeletal muscle and agree with the notion that CaMKK is an upstream kinase of AMPK in the regulation of substrate metabolism in skeletal muscle.

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