Effects of intensified endurance training on the concentration of Na, K-ATPase and Ca-ATPase in human skeletal muscle

Pyruvate dehydrogenase (PDH) is a mitochondrial enzyme responsible for regulating the conversion of pyruvate to acetyl-CoA for use in the tricarboxylic acid cycle. PDH is regulated through phosphorylation and inactivation by PDH kinase (PDK) and dephosphorylation and activation by PDH phosphatase (PDP). The effect of endurance training on PDK in humans has been investigated; however, to date no study has examined the effect of endurance training on PDP in humans. Therefore, the purpose of this study was to examine differences in PDP activity and PDP1 protein content in human skeletal muscle across a range of muscle aerobic capacities. This association is important as higher PDP activity and protein content will allow for increased activation of PDH, and carbohydrate oxidation. The main findings of this study were that 1) PDP activity ( r2 = 0.399, P = 0.001) and PDP1 protein expression ( r2 = 0.153, P = 0.039) were positively correlated with citrate synthase (CS) activity as a marker for muscle aerobic capacity; 2) E1α ( r2 = 0.310, P = 0.002) and PDK2 protein ( r2 = 0.229, P =0.012) are positively correlated with muscle CS activity; and 3) although it is the most abundant isoform, PDP1 protein content only explained ∼18% of the variance in PDP activity ( r2 = 0.184, P = 0.033). In addition, PDP1 in combination with E1α explained ∼38% of the variance in PDP activity ( r2 = 0.383, P = 0.005), suggesting that there may be alternative regulatory mechanisms of this enzyme other than protein content. These data suggest that with higher muscle aerobic capacity (CS activity) there is a greater capacity for carbohydrate oxidation (E1α), in concert with higher potential for PDH activation (PDP activity).

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Short-term sprint intervalversustraditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance

The Journal of Physiology ◽

10.1113/jphysiol.2006.112094 ◽

2006 ◽

Vol 575 (3) ◽

pp. 901-911 ◽

Cited By ~ 556

Author(s):

Martin J. Gibala ◽

Jonathan P. Little ◽

Martin Van Essen ◽

Geoffrey P. Wilkin ◽

Kirsten A. Burgomaster ◽

...

Keyword(s):

Skeletal Muscle ◽

Endurance Training ◽

Exercise Performance ◽

Human Skeletal Muscle ◽

Short Term

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Regulation of miRNAs in human skeletal muscle following acute endurance exercise and short-term endurance training

The Journal of Physiology ◽

10.1113/jphysiol.2013.255695 ◽

2013 ◽

Vol 591 (18) ◽

pp. 4637-4653 ◽

Cited By ~ 131

Author(s):

Aaron P. Russell ◽

Severine Lamon ◽

Hanneke Boon ◽

Shogo Wada ◽

Isabelle Güller ◽

...

Keyword(s):

Skeletal Muscle ◽

Endurance Training ◽

Endurance Exercise ◽

Human Skeletal Muscle ◽

Short Term

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Effects of 7 wk of endurance training on human skeletal muscle metabolism during submaximal exercise

Journal of Applied Physiology ◽

10.1152/japplphysiol.00517.2004 ◽

2004 ◽

Vol 97 (6) ◽

pp. 2148-2153 ◽

Cited By ~ 30

Author(s):

Paul J. LeBlanc ◽

Krista R. Howarth ◽

Martin J. Gibala ◽

George J. F. Heigenhauser

Keyword(s):

Skeletal Muscle ◽

Endurance Training ◽

Glycogen Phosphorylase ◽

Human Skeletal Muscle ◽

Vastus Lateralis ◽

Muscle Metabolism ◽

Allosteric Modulators ◽

Before And After ◽

First Time ◽

Muscle Biopsies

This is the first study to examine the effects of endurance training on the activation state of glycogen phosphorylase (Phos) and pyruvate dehydrogenase (PDH) in human skeletal muscle during exercise. We hypothesized that 7 wk of endurance training (Tr) would result in a posttransformationally regulated decrease in flux through Phos and an attenuated activation of PDH during exercise due to alterations in key allosteric modulators of these important enzymes. Eight healthy men (22 ± 1 yr) cycled to exhaustion at the same absolute workload (206 ± 5 W; ∼80% of initial maximal oxygen uptake) before and after Tr. Muscle biopsies (vastus lateralis) were obtained at rest and after 5 and 15 min of exercise. Fifteen minutes of exercise post-Tr resulted in an attenuated activation of PDH (pre-Tr: 3.75 ± 0.48 vs. post-Tr: 2.65 ± 0.38 mmol·min−1·kg wet wt−1), possibly due in part to lower pyruvate content (pre-Tr: 0.94 ± 0.14 vs. post-Tr: 0.46 ± 0.03 mmol/kg dry wt). The decreased pyruvate availability during exercise post-Tr may be due to a decreased muscle glycogenolytic rate (pre-Tr: 13.22 ± 1.01 vs. post-Tr: 7.36 ± 1.26 mmol·min−1·kg dry wt−1). Decreased glycogenolysis was likely mediated, in part, by posttransformational regulation of Phos, as evidenced by smaller net increases in calculated muscle free ADP (pre-Tr: 111 ± 16 vs. post-Tr: 84 ± 10 μmol/kg dry wt) and Pi (pre-Tr: 57.1 ± 7.9 vs. post-Tr: 28.6 ± 5.6 mmol/kg dry wt). We have demonstrated for the first time that several signals act to coordinately regulate Phos and PDH, and thus carbohydrate metabolism, in human skeletal muscle after 7 wk of endurance training.

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