scholarly journals Hormone-sensitive lipase preferentially redistributes to lipid droplets associated with perilipin-5 in human skeletal muscle during moderate-intensity exercise

2018 ◽  
Vol 596 (11) ◽  
pp. 2077-2090 ◽  
Author(s):  
Katie L. Whytock ◽  
Sam O. Shepherd ◽  
Anton J. M. Wagenmakers ◽  
Juliette A. Strauss
Keyword(s):  
Skeletal Muscle ◽  
Lipid Droplets ◽  
Human Skeletal Muscle ◽  
Hormone Sensitive Lipase ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Hormone Sensitive ◽  
Perilipin 5

scholarly journals Regulation and role of hormone-sensitive lipase activity in human skeletal muscle

2004 ◽  
Vol 63 (2) ◽  
pp. 315-322 ◽  
Author(s):  
Matthew J. Watt ◽  
Lawrence L. Spriet
Keyword(s):  
Skeletal Muscle ◽  
Aerobic Exercise ◽  
Human Skeletal Muscle ◽  
Fatty Acyl ◽  
Hormone Sensitive Lipase ◽  
Moderate Intensity ◽  
Control Points ◽  
Moderate Intensity Exercise ◽  
Hormone Sensitive

Hormone-sensitive lipase (HSL) is believed to play a regulatory role in initiating the degradation of intramuscular triacylglycerol (IMTG) in skeletal muscle. A series of studies designed to characterise the response of HSL to three stimuli: exercise of varying intensities and durations; adrenaline infusions; altered fuel supply have recently been conducted in human skeletal muscle. In an attempt to understand the regulation of HSL activity the changes in the putative intramuscular and hormonal regulators of the enzyme have also been measured. In human skeletal muscle at rest there is a high constitutive level of HSL activity, which is not a function of biopsy freezing. The combination of low adrenaline and Ca2+levels and resting levels of insulin appear to dictate the level of HSL activity at rest. During the initial minute of low and moderate aerobic exercise HSL is activated by contractions in the apparent absence of increases in circulating adrenaline. During intense aerobic exercise, adrenaline may contribute to the early activation of HSL. The contraction-induced activation may be related to increased Ca2+and/or other unknown intramuscular activators. As low- and moderate-intensity exercise continues beyond a few minutes, activation by adrenaline through the cAMP cascade may also occur. With prolonged moderate-intensity exercise beyond 1–2 h and sustained high-intensity exercise, HSL activity decreases despite continuing increases in adrenaline, possibly as a result of increasing accumulations of free AMP, activation of AMP kinase and phosphorylation of inhibitory sites on HSL. The existing work in human skeletal muscle also suggests that there are numerous levels of control involved in the regulation of IMTG degradation, with control points downstream from HSL also being important. For example, it must be remembered that the actual flux (IMTG degradation) through HSL may be allosterically inhibited during prolonged exercise as a result of the accumulation of long-chain fatty acyl-CoA.

Progressive increase in human skeletal muscle AMPKα2 activity and ACC phosphorylation during exercise

2002 ◽  
Vol 282 (3) ◽  
pp. E688-E694 ◽  
Author(s):  
T. J. Stephens ◽  
Z.-P. Chen ◽  
B. J. Canny ◽  
B. J. Michell ◽  
B. E. Kemp ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Glycogen ◽  
Human Skeletal Muscle ◽  
Glycogen Content ◽  
Vastus Lateralis ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Western Blots ◽  
Muscle Glycogen Content ◽  
Muscle Creatine

The effect of prolonged moderate-intensity exercise on human skeletal muscle AMP-activated protein kinase (AMPK)α1 and -α2 activity and acetyl-CoA carboxylase (ACCβ) and neuronal nitric oxide synthase (nNOSμ) phosphorylation was investigated. Seven active healthy individuals cycled for 30 min at a workload requiring 62.8 ± 1.3% of peak O2consumption (V˙o 2 peak) with muscle biopsies obtained from the vastus lateralis at rest and at 5 and 30 min of exercise. AMPKα1 activity was not altered by exercise; however, AMPKα2 activity was significantly ( P < 0.05) elevated after 5 min (∼2-fold), and further elevated ( P < 0.05) after 30 min (∼3-fold) of exercise. ACCβ phosphorylation was increased ( P < 0.05) after 5 min (∼18-fold compared with rest) and increased ( P< 0.05) further after 30 min of exercise (∼36-fold compared with rest). Increases in AMPKα2 activity were significantly correlated with both increases in ACCβ phosphorylation and reductions in muscle glycogen content. Fat oxidation tended ( P = 0.058) to increase progressively during exercise. Muscle creatine phosphate was lower ( P < 0.05), and muscle creatine, calculated free AMP, and free AMP-to-ATP ratio were higher ( P < 0.05) at both 5 and 30 min of exercise compared with those at rest. At 30 min of exercise, the values of these metabolites were not significantly different from those at 5 min of exercise. Phosphorylation of nNOSμ was variable, and despite the mean doubling with exercise, statistically significance was not achieved ( P = 0.304). Western blots indicated that AMPKα2 was associated with both nNOSμ and ACCβ consistent with them both being substrates of AMPKα2 in vivo. In conclusion, AMPKα2 activity and ACCβ phosphorylation increase progressively during moderate exercise at ∼60% of V˙o 2 peak in humans, with these responses more closely coupled to muscle glycogen content than muscle AMP/ATP ratio.

Glutamine supplementation promotes anaplerosis but not oxidative energy delivery in human skeletal muscle

2001 ◽  
Vol 280 (4) ◽  
pp. E669-E675 ◽  
Author(s):  
Mark Bruce ◽  
Dumitru Constantin-Teodosiu ◽  
Paul L. Greenhaff ◽  
Leslie H. Boobis ◽  
Clyde Williams ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Vastus Lateralis ◽  
Tca Cycle ◽  
Glutamine Supplementation ◽  
Moderate Intensity ◽  
Vastus Lateralis Muscle ◽  
Energy Status ◽  
Moderate Intensity Exercise ◽  
Significant Difference

The aims of the present study were twofold: first to investigate whether TCA cycle intermediate (TCAI) pool expansion at the onset of moderate-intensity exercise in human skeletal muscle could be enhanced independently of pyruvate availability by ingestion of glutamine or ornithine α-ketoglutarate, and second, if it was, whether this modification of TCAI pool expansion had any effect on oxidative energy status during subsequent exercise. Seven males cycled for 10 min at ∼70% maximal O2 uptake 1 h after consuming either an artificially sweetened placebo (5 ml/kg body wt solution, CON), 0.125 g/kg body wtl-(+)-ornithine α-ketoglutarate dissolved in 5 ml/kg body wt solution (OKG), or 0.125 g/kg body wt l-glutamine dissolved in 5 ml/kg body wt solution (GLN). Vastus lateralis muscle was biopsied 1 h postsupplement and after 10 min of exercise. The sum of four measured TCAI (ΣTCAI; citrate, malate, fumarate, and succinate, ∼85% of total TCAI pool) was not different between conditions 1 h postsupplement. However, after 10 min of exercise, ΣTCAI (mmol/kg dry muscle) was greater in the GLN condition (4.90 ± 0.61) than in the CON condition (3.74 ± 0.38, P < 0.05) and the OKG condition (3.85 ± 0.28). After 10 min of exercise, muscle phosphocreatine (PCr) content was significantly reduced ( P < 0.05) in all conditions, but there was no significant difference between conditions. We conclude that the ingestion of glutamine increased TCAI pool size after 10 min of exercise most probably because of the entry of glutamine carbon at the level of α-ketoglutarate. However, this increased expansion in the TCAI pool did not appear to increase oxidative energy production, because there was no sparing of PCr during exercise.

Intramuscular triacylglycerol utilization in human skeletal muscle during exercise: is there a controversy?

2002 ◽  
Vol 93 (4) ◽  
pp. 1185-1195 ◽  
Author(s):  
Matthew J. Watt ◽  
George J. F. Heigenhauser ◽  
Lawrence L. Spriet
Keyword(s):  
Skeletal Muscle ◽  
Muscle Biopsy ◽  
Human Skeletal Muscle ◽  
Moderate Intensity ◽  
Resonance Spectroscopy ◽  
Moderate Exercise ◽  
Moderate Intensity Exercise ◽  
Trained Subjects ◽  
Skeletal Muscle Biopsy ◽  
Isotope Tracer

Intramuscular triacylglyerols (IMTGs) represent a potentially important energy source for contracting human skeletal muscle. Although the majority of evidence from isotope tracer and 1H-magnetic resonance spectroscopy (MRS) studies demonstrate IMTG utilization during exercise, controversy regarding the importance of IMTG as a metabolic substrate persists. The controversy stems from studies that measure IMTG in skeletal muscle biopsy samples and report no significant net IMTG degradation during prolonged moderate-intensity (55–70% maximal O2 consumption) exercise lasting 90–120 min. Although postexercise decrements in IMTG levels are often reported from direct muscle measurements, the marked between-biopsy variability (∼23%) that has been reported with this technique in untrained subjects is larger than the expected decrease in IMTG content, effectively precluding significant findings. In contrast, recent data obtained in endurance-trained subjects demonstrated reduced variability between duplicate biopsies (∼12%), and significant changes in IMTG were detected after 120 min of moderate-intensity exercise. Therefore, it is our contention that the muscle biopsy, isotope tracer, and 1H-MRS techniques report significant and energetically important oxidation of free fatty acids derived from IMTGs during prolonged moderate exercise.

scholarly journals Regulation of hormone-sensitive lipase activity and Ser563and Ser565phosphorylation in human skeletal muscle during exercise

2004 ◽  
Vol 560 (2) ◽  
pp. 551-562 ◽  
Author(s):  
Carsten Roepstorff ◽  
Bodil Vistisen ◽  
Morten Donsmark ◽  
Jakob N. Nielsen ◽  
Henrik Galbo ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Lipase Activity ◽  
Human Skeletal Muscle ◽  
Hormone Sensitive Lipase ◽  
Hormone Sensitive
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