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Effect of exercise intensity and hypoxia on skeletal muscle AMPK signaling and substrate metabolism in humans

Wadley, G. D and Lee-Young, Robert S and Canny, Benedict J and Wasuntarawat, Chanchira and Chen, Zejian and Hargreaves, Mark and Kemp, Bruce E and McConell, Glenn K (2006) Effect of exercise intensity and hypoxia on skeletal muscle AMPK signaling and substrate metabolism in humans. American Journal of Physiology - Endocrinology and Metabolism, 290 (4). E694-E702. ISSN 0193-1849

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Abstract

We compared in human skeletal muscle the effect of absolute vs. relative exercise intensity on AMP-activated protein kinase (AMPK) signaling and substrate metabolism under normoxic and hypoxic conditions. Eight untrained males cycled for 30 min under hypoxic conditions (11.5% O2, 111 ± 12 W, 72 ± 3% hypoxia O2 peak; 72% Hypoxia) or under normoxic conditions (20.9% O2) matched to the same absolute (111 ± 12 W, 51 ± 1% normoxia O2 peak; 51% Normoxia) or relative (to O2 peak) intensity (171 ± 18 W, 73 ± 1% normoxia O2 peak; 73% Normoxia). Increases (P < 0.05) in AMPK activity, AMPKα Thr172 phosphorylation, ACCbeta Ser221 phosphorylation, free AMP content, and glucose clearance were more influenced by the absolute than by the relative exercise intensity, being greatest in 73% Normoxia with no difference between 51% Normoxia and 72% Hypoxia. In contrast to this, increases in muscle glycogen use, muscle lactate content, and plasma catecholamine concentration were more influenced by the relative than by the absolute exercise intensity, being similar in 72% Hypoxia and 73% Normoxia, with both trials higher than in 51% Normoxia. In conclusion, increases in muscle AMPK signaling, free AMP content, and glucose disposal during exercise are largely determined by the absolute exercise intensity, whereas increases in plasma catecholamine levels, muscle glycogen use, and muscle lactate levels are more closely associated with the relative exercise intensity.

Item Type: Article
Uncontrolled Keywords: ResPubID22133. metabolic regulation, glucose kinetics, contraction, intense exercise, hypoxia, normoxia, skeletal muscle, metabolism, proteins, AMPK, kinase
Subjects: FOR Classification > 1106 Human Movement and Sports Science
Faculty/School/Research Centre/Department > Institute of Sport, Exercise and Active Living (ISEAL)
Depositing User: VUIR
Date Deposited: 13 Feb 2012 23:05
Last Modified: 12 Feb 2015 03:42
URI: http://vuir.vu.edu.au/id/eprint/8087
DOI: 10.​1152/​ajpendo.​00464.​2005
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Citations in Scopus: 32 - View on Scopus

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