| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.62116864 |
| AIMS / HYPOTHESIS : Leptin has been shown to activate AMP activated protein kinase ( AMPK ) , an enzyme that regulates the activities of key enzymes of lipid synthesis and metabolism . 0.62116864^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.75688754 |
| In addition , leptin has been shown previously to activate AMP activated kinase ( AMPK ) in skeletal muscle . 0.75688754^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Here we show that leptin selectively stimulates phosphorylation and activation of the alpha 2 catalytic subunit of AMPK ( alpha 2 AMPK ) in skeletal muscle , thus establishing a previously unknown signalling pathway for leptin . ^^^ Early activation of AMPK occurs by leptin acting directly on muscle , whereas later activation depends on leptin functioning through the hypothalamic sympathetic nervous system axis . ^^^ In parallel with its activation of AMPK , leptin suppresses the activity of ACC , thereby stimulating the oxidation of fatty acids in muscle . ^^^ Blocking AMPK activation inhibits the phosphorylation of ACC stimulated by leptin . ^^^ Our data identify AMPK as a principal mediator of the effects of leptin on fatty acid metabolism in muscle . . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Leptin has also been shown to increase fatty acid oxidation in skeletal muscle through the activation of AMPK . ^^^ However , we demonstrate that leptin had no significant effect on AMPK activity , AMPK phosphorylation state , ACC activity , or malonyl CoA levels . ^^^ AMPK activity and its phosphorylation state were also unaffected after 5 and 10 min of perfusion in the presence of leptin . ^^^ We also show that the effects of leptin in the heart are independent of changes in the AMPK ACC malonyl CoA axis . . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| AMPK expression and phosphorylation are increased in rodent muscle after chronic leptin treatment . ^^^ Acute stimulation of AMP activated protein kinase ( AMPK ) results in a repartitioning of FA toward oxidation and away from esterification in rodent soleus muscle and has recently been shown to be responsible , at least in part , for the acute stimulatory effect of leptin on FA oxidation . ^^^ Therefore , we hypothesized that the effects of chronic leptin treatment on muscle FA metabolism are mediated in part through an increased expression and / or activation of AMPK and a subsequent phosphorylation of acetyl CoA carboxylase and a decrease in malonyl CoA content . ^^^ Chronic leptin treatment resulted in an approximately 2 to 3 fold greater protein expression of AMPK catalytic ( alpha ( 2 ) ) and regulatory ( beta ( 2 ) ) units as well as a 1 . 5 to 2 fold increase in Thr ( 172 ) phosphorylation of AMPK in both soleus and white gastrocnemius muscles . ^^^ However , taken as a whole , our data support recent evidence in rodent muscle that leptin stimulates FA oxidation through stimulation of AMPK and a subsequent downregulation of ACC activity . . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| AMP activated protein kinase ( AMPK ) is a multisubstrate enzyme activated by increases in AMP during metabolic stress caused by exercise , hypoxia , lack of cell nutrients , as well as hormones , including adiponectin and leptin . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Recent studies suggest that the ability of leptin , adiponectin , 5 ' aminoimidazole 4 carboxamide riboside ( AICAR ) , adrenergic agonists , and metformin to diminish adiposity may be mediated , at least in part , by AMPK activation in peripheral tissues . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Although fasting caused the expected changes in body weight , plasma leptin , and free fatty acids , it did not increase AMPK activity in heart or skeletal muscle and only increased liver AMPK activity by approximately 20 % ( P = 0 . 10 ) . ^^^ Likewise , CR caused the expected changes in body weight , plasma leptin , and free fatty acids but did not alter AMPK activity in any of the three tissues . ^^^ Plasma leptin , a putative activator of AMPK , varied eightfold across the four groups of mice in the absence of changes in AMPK activity in any tissue . ^^^ We conclude that , although the metabolic adaptations to fasting and CR include changes in plasma leptin concentration and phosphorylated acetyl CoA carboxylase , these effects occur without changes in AMPK activity . . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| We also examined the effect of 5 aminoimidazole 4 carboxamide riboside ( AICAR ) on AMPK activity and the effects of AICAR and leptin on FA metabolism . ^^^ We conclude that the abnormal lipid metabolism and leptin resistance of skeletal muscle of obese subjects is not due to down regulation of AMPK . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| The finding that leptin and adiponectin activate AMPK to alter metabolic pathways in muscle and liver provides direct evidence for this role in peripheral tissues . ^^^ In vivo administration of leptin , which leads to a reduction in food intake , decreases hypothalamic AMPK activity . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Whether metformin or the satiety factor leptin , which also stimulates AMPK in muscle , regulates this enzyme in pancreatic islets is unknown . ^^^ Here , we explore whether 1 ) glucose , metformin , or leptin regulates AMPK activity in isolated islets from rodent and human and 2 ) whether changes in AMPK activity modulate insulin secretion from human islets . ^^^ Incubation with metformin ( 0 . 2 1 mM ) activated AMPK in both human islets and MIN 6 beta cells in parallel with an inhibition of insulin secretion , whereas leptin ( 10 100 nM ) was without effect in MIN 6 cells . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Besides Jak / STAT , other pathways , such as MAPK and the 5 ' AMP activated protein kinase ( AMPK ) pathway , are also involved in leptin signalling . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Here we report that AMPK activity is inhibited in arcuate and paraventricular hypothalamus ( PVH ) by the anorexigenic hormone leptin , and in multiple hypothalamic regions by insulin , high glucose and refeeding . ^^^ Melanocortin receptor signalling is required for leptin and refeeding effects on AMPK in PVH . ^^^ Furthermore , inhibition of hypothalamic AMPK is necessary for leptin ' s effects on food intake and body weight , as constitutively active AMPK blocks these effects . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| New evidence suggests that leptin and other anorexigenic agents reduce appetite by inactivating hypothalamic AMP activated protein kinase ( AMPK ) , thereby increasing malonyl CoA levels . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| We report here studies that integrate data of respiration rate from mouse skeletal muscle in response to leptin and pharmacological interference with intermediary metabolism , together with assays for phosphatidylinositol 3 kinase ( PI3K ) and AMP activated protein kinase ( AMPK ) . ^^^ Our results suggest that the direct effect of leptin in stimulating thermogenesis in skeletal muscle is mediated by substrate cycling between de novo lipogenesis and lipid oxidation , and that this cycle requires both PI3K and AMPK signaling . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Moreover , it has been shown that AMPK in adipocytes can be activated by adipocyte derived hormones leptin and adiponectin , and also by insulin sensitizes thiazolidinediones . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Polyunsaturated fatty acids ( PUFA ) and a number of drugs ( metformin , thiazolidinediones ) and hormones ( leptin , adiponectin ) that activate AMP activated protein kinase ( AMPK ) have been reported to improve insulin sensitivity . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Intracerebroventricular administration of leptin and insulin reduced hyperphagia and the enhanced hypothalamic AMPK activity in diabetic rats . ^^^ These data suggest that leptin and insulin deficiencies in diabetes lead to increased hypothalamic AMPK activity , which contributes to the development of diabetic hyperphagia . . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| The fuel sensing enzyme 5 ' AMP activated protein kinase ( AMPK ) has a major role in the regulation of cellular lipid and protein metabolism in response to stimuli such as exercise , changes in fuel availability and the adipocyte derived hormones leptin and adiponectin . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| The adipocyte derived hormones , leptin and adiponectin , activate AMPK in peripheral tissues , including skeletal muscle and liver , increasing energy expenditure . ^^^ In the hypothalamus , AMPK is inhibited by leptin and insulin , hormones which suppress feeding , whilst ghrelin , a hormone that increases food intake , activates AMPK . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| In addition to its effects on the periphery , AMPK has been found to play a key role in the control of food intake through its regulation by hormones , including leptin , within the hypothalamus . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| AMPKalpha protein levels as well as basal and leptin stimulated total and alpha specific AMPK activity were comparable in both groups . ^^^ These data show that in a model of dietary induced obesity 1 ) leptin receptors and subsequent signaling events are down regulated , 2 ) basal insulin signaling is impaired , and 3 ) the cross talk between leptin and insulin signaling is differentially regulated by the nutritional status , which is sensed by AMPK in rat liver . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Recent studies from our group and others have shown that many factors ( alpha lipoic acid , leptin , insulin , ghrelin , glucose , 2 deoxyglucose , etc . ) cause an alteration in hypothalamic AMPK activity that mediates effects on feeding behavior . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Administration of leptin in rodents increases skeletal muscle beta oxidation by activating AMP activated protein kinase ( AMPK ) . ^^^ To assess skeletal muscle AMPK activity in leptin sensitive and insensitive states , we examined phosphorylation of AMPK and its target , acetyl CoA carboxylase ( ACC ) , in muscles from LepTg under dietary modification . ^^^ In conclusion , soleus AMPK and ACC phosphorylation in LepTg changes in parallel with its insulin sensitivity under dietary modification , suggesting a close association between skeletal muscle AMPK activity and sensitivity to leptin . . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Energy status is monitored by the cellular AMP activated protein kinase ( AMPK ) system , whereas leptin regulates total energy balance . ^^^ We investigated the roles of AMPK and leptin in cognition and survival under diet restriction ( DR ) . ^^^ Leptin signaling is preserved only in DR to 60 % , countering the effects of AMPK `` overactivation ' ' by preventing neuroapoptosis , restoring noradrenergic activity and behavioral performance , and increasing longevity . ^^^ The balance between leptin and AMPK is crucial in determining neuronal fate , cognitive ability , and survival . ^^^ Should these findings extend to Man , then controlled activation of AMPK may improve neurodegenerative diseases , and leptin may have a new role in treating stress associated malnutrition . . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Importantly , the adipocyte hormones leptin and adiponectin also activate AMPK ; remarkably , the same pathway is activated by certain antidiabetic agents such as thiazolidinediones . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Recent studies have shown that AMPK is the cellular mediator for many of the metabolic effects of drugs such as metformin and thiazolidinediones , as well as the insulin sensitizing adipocytokines leptin and adiponectin . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Alpha lipoic acid ( alpha LA ) mimics the hypothalamic actions of leptin on food intake , energy expenditure , and activation of AMP activated protein kinase ( AMPK ) . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Both leptin and CNTF reduced AMPK activity and acetyl coenzyme A carboxylase phosphorylation in the ARC and PVN of control fed mice . ^^^ A HFD blunted leptin but not CNTF effects on AMPK signaling in the ARC and PVN . ^^^ In summary , these data demonstrate that CNTF ( Ax 15 ) bypasses diet induced leptin resistance to reduce hypothalamic AMPK activity . . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| AMP activated protein kinase ( AMPK ) is a key regulator of cellular energy balance and of the effects of leptin on food intake and fatty acid oxidation . ^^^ To determine whether diet induced obesity ( DIO ) impairs the AMPK response to leptin in muscle and / or hypothalamus , we fed FVB mice a high fat ( 55 % ) diet for 10 12 weeks . ^^^ Leptin ( 3 mg / kg intraperitoneally ) increased alpha 2 AMPK activity 2 fold in muscle in chow fed mice but not in DIO mice . ^^^ In paraventricular , arcuate , and medial hypothalamus of chow fed mice , leptin inhibited alpha 2 AMPK activity but not in DIO mice . ^^^ Thus , DIO in FVB mice alters alpha 2 AMPK in muscle and hypothalamus and STAT 3 in hypothalamus and impairs further effects of leptin on these signaling pathways . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| Leptin and adiponectin as well as hypoglycaemic drugs are activators of adipose tissue AMPK . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| However , DEX reduced leptin induced STAT 3 phosphorylation in the cortex and hypothalamus , and it increased AMP activated protein kinase ( AMPK ) phosphorylation only in the hypothalamus . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| These results indicated that both decreased body weight and enhanced muscle AMPK activity in aP 2 mal1 ( / ) mice are potentially leptin dependent but improved systemic insulin sensitivity and protection from liver fatty infiltration are largely unrelated to leptin action and that insulin sensitizing effects of FABP deficiency are , at least in part , independent of its effects on total body adiposity . . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| CONTEXT : Leptin is thought to regulate whole body adiposity and insulin sensitivity , at least in part , by stimulating fatty acid metabolism via activation of AMP kinase ( AMPK ) in skeletal muscle . ^^^ OBJECTIVE : The objective of the study was to investigate the effects of leptin on fatty acid oxidation and AMPK signaling in primary myotubes derived from lean and obese skeletal muscle and evaluate the contribution of SOCS 3 to leptin resistance and AMPK signaling in obese humans . ^^^ RESULTS : We demonstrate that leptin stimulates AMPK activity and increases AMPK Thr 172 and acetyl CoA carboxylase beta Ser 222 phosphorylation and fatty acid oxidation in lean myotubes but that in obese subjects leptin dependent AMPK signaling and fatty acid oxidation are suppressed . ^^^ Overexpression of SOCS 3 via adenovirus mediated infection in lean myotubes to a similar degree as observed in obese myotubes prevented leptin but not AICAR ( 5 amino imidazole 4 carboxamide 1 beta d ribofuranoside ) activation of AMPK signaling . ^^^ CONCLUSIONS : These data demonstrate that SOCS 3 inhibits leptin activation of AMPK . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| By responding to diverse hormonal signals including leptin and adiponectin , AMPK serves as an intertissue signal integrator among peripheral tissues , as well as the hypothalamus , in the control of whole body energy balance . . ^^^ |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| NA |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| NA |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| NA |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| NA |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| NA |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| NA |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| NA |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| NA |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| NA |
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| Interacting proteins: P41159 and P54646 |
Pubmed |
SVM Score :0.0 |
| NA |
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