Kinetics of post-exercise phosphate transport in human skeletal muscle: An in vivo 31P-MR spectroscopy study

A mathematical model analogous to Chance's “transfer function” was derived on the basis of the energy consumption principle, which is suitable to describe the energetics of human skeletal muscle during aerobic activity. The implications and the characteristics of this model are that 1) the half time of phosphocreatine (PCr) hydrolysis at the onset of a mechanical constant-load exercise is independent of the imposed charge, 2) the changes of O2 consumption in the muscle at steady state when changing workload are linearly related to PCr concentration, 3) the kinetics of the intracellular oxygen consumption during a rest-to-work transient are influenced by anaerobic glycolysis, 4) it may explain the PCr-time relationship of different muscles types (e.g., skeletal, heart, trained vs. untrained), 5) it allows one to interpret correctly the significance of the oxygen consumption kinetics in the rest-to-work transient at the lung level, and 6) it is conceived for in vivo applications.

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Hyperpolarized 13C MR Spectroscopy Depicts in Vivo Effect of Exercise on Pyruvate Metabolism in Human Skeletal Muscle

Radiology ◽

10.1148/radiol.2021204500 ◽

2021 ◽

pp. 204500

Author(s):

Jae Mo Park ◽

Crystal E. Harrison ◽

Junjie Ma ◽

Jun Chen ◽

James Ratnakar ◽

...

Keyword(s):

Skeletal Muscle ◽

Mr Spectroscopy ◽

Human Skeletal Muscle ◽

Pyruvate Metabolism ◽

Hyperpolarized 13C

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Effects of Oral Resveratrol Supplementation on Glycogen Replenishment and Mitochondria Biogenesis in Exercised Human Skeletal Muscle

Nutrients ◽

10.3390/nu12123721 ◽

2020 ◽

Vol 12 (12) ◽

pp. 3721

Author(s):

Chun-Ching Huang ◽

Chia-Chen Liu ◽

Jung-Piao Tsao ◽

Chin-Lin Hsu ◽

I-Shiung Cheng

Keyword(s):

Skeletal Muscle ◽

Glucose Uptake ◽

Muscle Glycogen ◽

Human Skeletal Muscle ◽

Young Male ◽

Gene Expressions ◽

Plasma Parameters ◽

Post Exercise ◽

Glycogen Resynthesis ◽

Mitochondria Biogenesis

The present study aimed to investigate the effect of oral resveratrol supplementation on the key molecular gene expressions involved in mitochondria biogenesis and glycogen resynthesis in human skeletal muscle. Nine young male athletes participated in the single-blind and crossover designed study. All subjects completed a 4-day resveratrol and placebo supplement in a randomized order while performing a single bout of cycling exercise. Immediately after the exercise challenge, the subjects consumed a carbohydrate (CHO) meal (2 g CHO/Kg body mass) with either resveratrol or placebo capsules. Biopsied muscle samples, blood samples and expired gas samples were obtained at 0 h and 3 h after exercise. The muscle samples were measured for gene transcription factor expression by real-time PCR for glucose uptake and mitochondria biogenesis. Plasma glucose, insulin, glycerol, non-esterified fatty acid concentrations and respiratory exchange ratio were analyzed during post-exercise recovery periods. The results showed that the muscle glycogen concentrations were higher at 3 h than at 0 h; however, there were no difference between resveratrol trial and placebo trial. There were no significantly different concentrations in plasma parameters between the two trials. Similarly, no measured gene expressions were significant between the two trials. The evidence concluded that the 4-day oral resveratrol supplementation did not improve post-exercise muscle glycogen resynthesis and related glucose uptake and mitochondrial biosynthesis gene expression in men.

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Physical exercise increases autophagic signaling through ULK1 in human skeletal muscle

Journal of Applied Physiology ◽

10.1152/japplphysiol.01116.2014 ◽

2015 ◽

Vol 118 (8) ◽

pp. 971-979 ◽

Cited By ~ 58

Author(s):

Andreas Buch Møller ◽

Mikkel Holm Vendelbo ◽

Britt Christensen ◽

Berthil Forrest Clasen ◽

Ann Mosegaard Bak ◽

...

Keyword(s):

Skeletal Muscle ◽

Physical Exercise ◽

Light Chain ◽

Human Skeletal Muscle ◽

Transgenic Animal ◽

Dependent Manner ◽

Healthy Humans ◽

Transgenic Animal Models ◽

Exercise Induced

Data from transgenic animal models suggest that exercise-induced autophagy is critical for adaptation to physical training, and that Unc-51 like kinase-1 (ULK1) serves as an important regulator of autophagy. Phosphorylation of ULK1 at Ser555 stimulates autophagy, whereas phosphorylation at Ser757 is inhibitory. To determine whether exercise regulates ULK1 phosphorylation in humans in vivo in a nutrient-dependent manner, we examined skeletal muscle biopsies from healthy humans after 1-h cycling exercise at 50% maximal O2 uptake on two occasions: 1) during a 36-h fast, and 2) during continuous glucose infusion at 0.2 kg/h. Physical exercise increased ULK1 phosphorylation at Ser555 and decreased lipidation of light chain 3B. ULK1 phosphorylation at Ser555 correlated positively with AMP-activated protein kinase-α Thr172 phosphorylation and negatively with light chain 3B lipidation. ULK1 phosphorylation at Ser757 was not affected by exercise. Fasting increased ULK1 and p62 protein expression, but did not affect exercise-induced ULK1 phosphorylation. These data demonstrate that autophagy signaling is activated in human skeletal muscle after 60 min of exercise, independently of nutritional status, and suggest that initiation of autophagy constitutes an important physiological response to exercise in humans.

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Promoter-specific regulation of PPARGC1A gene expression in human skeletal muscle

Journal of Molecular Endocrinology ◽

10.1530/jme-15-0150 ◽

2015 ◽

Vol 55 (2) ◽

pp. 159-168 ◽

Cited By ~ 12

Author(s):

Daniil V Popov ◽

Evgeny A Lysenko ◽

Tatiana F Vepkhvadze ◽

Nadia S Kurochkina ◽

Pavel A Maknovskii ◽

...

Keyword(s):

Gene Expression ◽

Skeletal Muscle ◽

Human Skeletal Muscle ◽

Stop Codon ◽

Constitutive Expression ◽

Alternative Promoter ◽

Specific Expression ◽

Post Exercise ◽

Specific Regulation ◽

Intensity Of Exercise

The goal of this study was to identify unknown transcription start sites of thePPARGC1A(PGC-1α) gene in human skeletal muscle and investigate the promoter-specific regulation ofPGC-1αgene expression in human skeletal muscle. Ten amateur endurance-trained athletes performed high- and low-intensity exercise sessions (70 min, 70% or 50%o2max). High-throughput RNA sequencing and exon–exon junction mapping were applied to analyse muscle samples obtained at rest and after exercise.PGC-1αpromoter-specific expression and activation of regulators of PGC-1α gene expression (AMPK, p38 MAPK, CaMKII, PKA and CREB1) after exercise were evaluated using qPCR and western blot. Our study has demonstrated that during post-exercise recovery, human skeletal muscle expresses thePGC-1αgene via two promoters only. As previously described, the additional exon 7a that contains a stop codon was found in all samples. Importantly, only minor levels of other splice site variants were found (and not in all samples). Constitutive expressionPGC-1αgene occurs via the canonical promoter, independent of exercise intensity and exercise-induced increase of AMPKThr172phosphorylation level. Expression ofPGC-1αgene via the alternative promoter is increased of two orders after exercise. This post-exercise expression is highly dependent on the intensity of exercise. There is an apparent association between expression via the alternative promoter and activation of CREB1.

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