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Carbohydrate ingestion does not alter skeletal muscle AMPK signaling during exercise in humans

Lee-Young, Robert S, Palmer, Matthew J, Linden, Kelly C, LePlastrier, Kieran, Canny, Benedict J, Hargreaves, Mark, Wadley, Glenn D, Kemp, Bruce E and McConell, Glenn ORCID: 0000-0002-8572-9065 (2006) Carbohydrate ingestion does not alter skeletal muscle AMPK signaling during exercise in humans. American Journal of Physiology - Endocrinology and Metabolism, 291 (3). E566-E573. ISSN 0193-1849

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Abstract

There is evidence that increasing carbohydrate (CHO) availability during exercise by raising preexercise muscle glycogen levels attenuates the activation of AMPKα2 during exercise in humans. Similarly, increasing glucose levels decreases AMPKα2 activity in rat skeletal muscle in vitro. We examined the effect of CHO ingestion on skeletal muscle AMPK signaling during exercise in nine active male subjects who completed two 120-min bouts of cycling exercise at 65 ± 1% O2 peak. In a randomized, counterbalanced order, subjects ingested either an 8% CHO solution or a placebo solution during exercise. Compared with the placebo trial, CHO ingestion significantly (P < 0.05) increased plasma glucose levels and tracer-determined glucose disappearance. Exercise-induced increases in muscle-calculated free AMP (17.7- vs. 11.8-fold), muscle lactate (3.3- vs. 1.8-fold), and plasma epinephrine were reduced by CHO ingestion. However, the exercise-induced increases in skeletal muscle AMPKα2 activity, AMPKα2 Thr172 phosphorylation and acetyl-CoA Ser222 phosphorylation, were essentially identical in the two trials. These findings indicate that AMPK activation in skeletal muscle during exercise in humans is not sensitive to changes in plasma glucose levels in the normal range. Furthermore, the rise in plasma epinephrine levels in response to exercise was greatly suppressed by CHO ingestion without altering AMPK signaling, raising the possibility that epinephrine does not directly control AMPK activity during muscle contraction under these conditions in vivo.

Item Type: Article
Uncontrolled Keywords: ResPubID22113. adenosine monophosphate-activated protein kinase, acetyl-coenzyme A carboxylase, contraction, glucose uptake, metabolism, carbohydrate ingestion, plasma, skeletal muscle, exercise
Subjects: FOR Classification > 1101 Medical Biochemistry and Metabolomics
FOR Classification > 1106 Human Movement and Sports Science
FOR Classification > 1111 Nutrition and Dietetics
Faculty/School/Research Centre/Department > Institute of Sport, Exercise and Active Living (ISEAL)
Depositing User: VUIR
Date Deposited: 30 Jan 2012 03:52
Last Modified: 02 May 2019 04:48
URI: http://vuir.vu.edu.au/id/eprint/8067
DOI: https://doi.org/10.​1152/​ajpendo.​00023.​2006
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Citations in Scopus: 26 - View on Scopus

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