scholarly journals Involvement of PPARγ co-activator-1, nuclear respiratory factors 1 and 2, and PPARα in the adaptive response to endurance exercise

2004 ◽  
Vol 63 (2) ◽  
pp. 269-273 ◽  
Author(s):  
Keith Baar
Keyword(s):  
Endurance Exercise ◽  
Glucose Transporter ◽  
The Elderly ◽  
Regulatory Proteins ◽  
Acid Oxidation ◽  
Genetic Response ◽  
Nuclear Respiratory Factors ◽  
Endurance Exercise Training ◽  
And Shifts ◽  
Glucose Transporter Glut4

Endurance exercise training induces an increase in the respiratory capacity of muscle, resulting in an increased capacity to generate ATP as well as improved efficiency of muscle contraction. Such adaptations are largely the result of a coordinated genetic response that increases mitochondrial proteins, fatty acid oxidation enzymes and the exercise- and insulin-stimulated glucose transporter GLUT4, and shifts the contractile and regulatory proteins to their more efficient isoforms. In recent years a number of the transcriptional regulators involved in this genetic response have been identified and these factors can be classified into two different groups. The first group comprises transcription factors such as nuclear respiratory factors (NRF) 1 and 2 and PPARα that bind DNA in a sequence-specific manner. The second group, referred to as transcriptional co-activators, alter transcription without directly binding to DNA. The PPARγ co-activator (PGC) family of proteins have been identified as the central family of transcriptional co-activators for induction of mitochondrial biogenesis. PGC-1α is activated by exercise, and is sufficient to produce the endurance phenotype through direct interactions with NRF-1 and PPARα, and potentially NRF-2. Furthering the understanding of the activation of PGC proteins following exercise has implications beyond improving athletic performance, including the possibility of providing targets for the treatment of frailty in the elderly, obesity and diseases such as mitochondrial myopathies and diabetes.

Higher mitochondrial fatty acid oxidation following intermittent versus continuous endurance exercise training

1998 ◽  
Vol 76 (9) ◽  
pp. 891-894 ◽  
Author(s):  
P D Chilibeck ◽  
G J Bell ◽  
R P Farrar ◽  
T P Martin
Keyword(s):  
Fatty Acid ◽  
Exercise Training ◽  
Fatty Acid Oxidation ◽  
Endurance Exercise ◽  
High Intensity ◽  
Treadmill Running ◽  
Acid Oxidation ◽  
Interval Exercise ◽  
Endurance Exercise Training ◽  
Mitochondrial Fatty Acid

It has been well documented that skeletal muscle fatty acid oxidation can be elevated by continuous endurance exercise training. However, it remains questionable whether similar adaptations can be induced with intermittent interval exercise training. This study was undertaken to directly compare the rates of fatty acid oxidation in isolated subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondria following these different exercise training regimes. Mitochondria were isolated from the gastrocnemius-plantaris muscles of male Sprague-Dawley rats following exercise training 6 days per week for 12 weeks. Exercise training consisted of either continuous, submaximal, endurance treadmill running (n = 10) or intermittent, high intensity, interval running (n = 10). Both modes of training enhanced the oxidation of palmityl-carnitine-malate in both mitochondrial populations (p < 0.05). However, the increase associated with the intermittent, high intensity exercise training was significantly greater than that achieved with the continuous exercise training (p < 0.05). Also, the increases associated with the IMF mitochondria were greater than the SS mitochondria (p < 0.05). These data suggest that high intensity, intermittent interval exercise training is more effective for stimulation of fatty acid oxidation than continuous submaximal exercise training and that this adaptation occurs preferentially within IMF mitochondria.Key words: muscle, subsarcolemmal mitochondria, intermyofibrillar mitochondria.

Effect of endurance exercise training on muscle glycogen supercompensation in rats

1997 ◽  
Vol 82 (2) ◽  
pp. 711-715 ◽  
Author(s):  
Akira Nakatani ◽  
Dong-Ho Han ◽  
Polly A. Hansen ◽  
Lorraine A. Nolte ◽  
Helen H. Host ◽  
...  
Keyword(s):  
Exercise Training ◽  
Endurance Exercise ◽  
Muscle Glycogen ◽  
Glucose Transporter ◽  
Glycogen Synthase ◽  
Recovery Period ◽  
Chow Diet ◽  
Glycogen Accumulation ◽  
Transporter Protein ◽  
Endurance Exercise Training

Nakatani, Akira, Dong-Ho Han, Polly A. Hansen, Lorraine A. Nolte, Helen H. Host, Robert C. Hickner, and John O. Holloszy.Effect of endurance exercise training on muscle glycogen supercompensation in rats. J. Appl. Physiol. 82(2): 711–715, 1997.—The purpose of this study was to test the hypothesis that the rate and extent of glycogen supercompensation in skeletal muscle are increased by endurance exercise training. Rats were trained by using a 5-wk-long swimming program in which the duration of swimming was gradually increased to 6 h/day over 3 wk and then maintained at 6 h/day for an additional 2 wk. Glycogen repletion was measured in trained and untrained rats after a glycogen-depleting bout of exercise. The rats were given a rodent chow diet plus 5% sucrose in their drinking water ad libitum during the recovery period. There were remarkable differences in both the rates of glycogen accumulation and the glycogen concentrations attained in the two groups. The concentration of glycogen in epitrochlearis muscle averaged 13.1 ± 0.9 mg/g wet wt in the untrained group and 31.7 ± 2.7 mg/g in the trained group ( P < 0.001) 24 h after the exercise. This difference could not be explained by a training effect on glycogen synthase. The training induced ∼50% increases in muscle GLUT-4 glucose transporter protein and in hexokinase activity in epitrochlearis muscles. We conclude that endurance exercise training results in increases in both the rate and magnitude of muscle glycogen supercompensation in rats.

scholarly journals Enhanced Fatty Acid Oxidation and FATP4 Protein Expression after Endurance Exercise Training in Human Skeletal Muscle

PLoS ONE ◽  
2012 ◽  
Vol 7 (1) ◽  
pp. e29391 ◽  
Author(s):  
Jacob Jeppesen ◽  
Andreas B. Jordy ◽  
Kim A. Sjøberg ◽  
Joachim Füllekrug ◽  
Andreas Stahl ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Exercise Training ◽  
Protein Expression ◽  
Fatty Acid Oxidation ◽  
Endurance Exercise ◽  
Human Skeletal Muscle ◽  
Acid Oxidation ◽  
Endurance Exercise Training

Coimmunoprecipitation of FAT/CD36 and CPT I in skeletal muscle increases proportionally with fat oxidation after endurance exercise training

2006 ◽  
Vol 291 (2) ◽  
pp. E254-E260 ◽  
Author(s):  
Simon Schenk ◽  
Jeffrey F. Horowitz
Keyword(s):  
Skeletal Muscle ◽  
Weight Loss ◽  
Fatty Acid ◽  
Exercise Training ◽  
Endurance Exercise ◽  
Dietary Intervention ◽  
Fat Oxidation ◽  
Acid Oxidation ◽  
Endurance Exercise Training ◽  
Cpt I

Although the increase in fatty acid oxidation after endurance exercise training has been linked with improvements in insulin sensitivity and overall metabolic health, the mechanisms responsible for increasing fatty acid oxidation after exercise training are not completely understood. The primary aim of this study was to determine the effect of adding endurance exercise training to a weight loss program on fat oxidation and the colocalization of the fatty acid translocase FAT/CD36 with carnitine palmitoyltransferase I (CPT I) in human skeletal muscle. We measured postabsorptive fat oxidation and acquired a muscle sample from abdominally obese women before and after 12% body weight loss through either dietary intervention with endurance exercise training (EX + DIET) or dietary intervention without endurance exercise training (DIET). Immunoprecipitation techniques were used on these muscle samples to determine whether the association between FAT/CD36 and CPT I is altered after DIET and/or EX + DIET. FAT/CD36 was found to coimmunoprecipitate with CPT I, and the amount of FAT/CD36 that coimmunoprecipitated with CPT I increased by ∼25% after EX + DIET ( P < 0.005) but was unchanged after DIET. In addition, the increase in the amount of FAT/CD36 that coimmunoprecipitated with CPT I in EX + DIET was strongly correlated with the increase in whole body fat oxidation ( R2 = 0.857, P < 0.003). In conclusion, the findings from this study indicate that exercise training alters the localization of FAT/CD36 and increases its association with CPT I, which may help augment fat oxidation.

scholarly journals Impact of SGLT2 Inhibitors on Heart Failure: From Pathophysiology to Clinical Effects

2021 ◽  
Vol 22 (11) ◽  
pp. 5863
Author(s):  
Giuseppe Palmiero ◽  
Arturo Cesaro ◽  
Erica Vetrano ◽  
Pia Clara Pafundi ◽  
Raffaele Galiero ◽  
...  
Keyword(s):  
Heart Failure ◽  
Glucose Transporter ◽  
The Elderly ◽  
Intracellular Sodium ◽  
Clinical Effects ◽  
Glucose Lowering ◽  
Beneficial Effects ◽  
Glucose Transporter 2 ◽  
Function Impairment

Heart failure (HF) affects up to over 20% of patients with type 2 diabetes (T2DM), even more in the elderly. Although, in T2DM, both hyperglycemia and the proinflammatory status induced by insulin resistance are crucial in cardiac function impairment, SGLT2i cardioprotective mechanisms against HF are several. In particular, these beneficial effects seem attributable to the significant reduction of intracellular sodium levels, well-known to exert a cardioprotective role in the prevention of oxidative stress and consequent cardiomyocyte death. From a molecular perspective, patients’ exposure to gliflozins’ treatment mimics nutrient and oxygen deprivation, with consequent autophagy stimulation. This allows to maintain the cellular homeostasis through different degradative pathways. Thus, since their introduction in the clinical practice, the hypotheses on SGLT2i mechanisms of action have changed: from simple glycosuric drugs, with consequent glucose lowering, erythropoiesis enhancing and ketogenesis stimulating, to intracellular sodium-lowering molecules. This provides their consequent cardioprotective effect, which justifies its significant reduction in CV events, especially in populations at higher risk. Finally, the updated clinical evidence of SGLT2i benefits on HF was summarized. Thus, this review aimed to analyze the cardioprotective mechanisms of sodium glucose transporter 2 inhibitors (SGLT2i) in patients with HF, as well as their clinical impact on cardiovascular events.

C2C12 myocytes lack an insulin-responsive vesicular compartment despite dexamethasone-induced GLUT4 expression

2002 ◽  
Vol 283 (3) ◽  
pp. E514-E524 ◽  
Author(s):  
Lori L. Tortorella ◽  
Paul F. Pilch
Keyword(s):  
Glucose Transporter ◽  
Fold Increase ◽  
Snare Proteins ◽  
Vesicular Traffic ◽  
Glut4 Expression ◽  
Protein Receptor ◽  
Syntaxin 4 ◽  
Insulin Dependent ◽  
Glucose Transporter Glut4 ◽  
Vesicular Compartment

Insulin regulates the uptake of glucose into skeletal muscle and adipocytes by redistributing the tissue-specific glucose transporter GLUT4 from intracellular vesicles to the cell surface. To date, GLUT4 is the only protein involved in insulin-regulated vesicular traffic that has this tissue distribution, thus raising the possibility that its expression alone may allow formation of an insulin-responsive vesicular compartment. We show here that treatment of differentiating C2C12myoblasts with dexamethasone, acting via the glucocorticoid receptor, causes a ≥10-fold increase in GLUT4 expression but results in no significant change in insulin-stimulated glucose transport. Signaling from the insulin receptor to its target, Akt2, and expression of the soluble N-ethylmaleimide-sensitive factor-attachment protein receptor, or SNARE, proteins syntaxin 4 and vesicle-associated membrane protein are normal in dexamethasone-treated C2C12 cells. However, these cells show no insulin-dependent trafficking of the insulin-responsive aminopeptidase or the transferrin receptor, respective markers for intracellular GLUT4-rich compartments and endosomes that are insulin responsive in mature muscle and adipose cells. Therefore, these data support the hypothesis that GLUT4 expression by itself is insufficient to establish an insulin-sensitive vesicular compartment.

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