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Effects of adenosine, exercise, and moderate acute hypoxia on energy substrate utilization of human skeletal muscle

Effects of adenosine, exercise, and moderate acute hypoxia on energy substrate utilization of... Abstract Glucose metabolism increases in hypoxia and can be influenced by endogenous adenosine, but the role of adenosine for regulating glucose metabolism at rest or during exercise in hypoxia has not been elucidated in humans. We studied the effects of exogenous adenosine on human skeletal muscle glucose uptake and other blood energy substrates (free fatty acid (FFA) and lactate) by infusing adenosine into the femoral artery in nine healthy young men. The role of endogenous adenosine was studied by intra-arterial adenosine receptor inhibition (aminophylline) during dynamic one-leg knee extension exercise in normoxia and acute hypoxia corresponding to ∼3,400 m of altitude. Extraction and release of energy substrates were studied by arterial-to-venous (A-V) blood samples, and total uptake or release was determined by the product of A-V differences and muscle nutritive perfusion measured by positron emission tomography. The results showed that glucose uptake increased from a baseline value of 0.2 ± 0.2 to 2.0 ± 2.2 μmol·100 g −1 ·min −1 during adenosine infusion ( P < 0.05) at rest. Although acute hypoxia enhanced arterial FFA levels, it did not affect muscle substrate utilization at rest. During exercise, glucose uptake was higher (195%) during acute hypoxia compared with normoxia ( P = 0.058), and aminophylline had no effect on energy substrate utilization during exercise, despite that arterial FFA levels were increased. In conclusion, exogenous adenosine at rest and acute moderate hypoxia during low-intensity knee-extension exercise increases skeletal muscle glucose uptake, but the increase in hypoxia appears not to be mediated by adenosine. glucose uptake Copyright © 2012 the American Physiological Society « Previous Table of Contents This Article Published online before print November 2011 , doi: 10.​1152/​ajpregu.​00245.​2011 AJP - Regu Physiol February 2012 vol. 302 no. 3 R385-R390 » Abstract Free Full Text Free to you Full Text (PDF) Free to you All Versions of this Article: ajpregu.00245.2011v1 302/3/R385 most recent Classifications Physical Activity and Inactivity Obesity, Diabetes and Energy Homeostasis Services Email this article to a friend Alert me when this article is cited Alert me if a correction is posted Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Download to citation manager Citing Articles Load citing article information Citing articles via Web of Science Google Scholar Articles by Heinonen, I. Articles by Kalliokoski, K. K. PubMed PubMed citation Articles by Heinonen, I. Articles by Kalliokoski, K. K. Related Content Load related web page information Current Issue February 2012, 302 (3) Alert me to new issues of AJP - Regu Physiol About the Journal Information for Authors Submit a Manuscript Ethical Policies AuthorChoice PubMed Central Policy Reprints and Permissions Advertising Press Copyright © 2012 the American Physiological Society Print ISSN: 0363-6119 Online ISSN: 1522-1490 var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); var pageTracker = _gat._getTracker("UA-2924550-1"); pageTracker._trackPageview(); http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png AJP - Regulatory, Integrative and Comparative Physiology The American Physiological Society

Effects of adenosine, exercise, and moderate acute hypoxia on energy substrate utilization of human skeletal muscle

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References (47)

Publisher
The American Physiological Society
Copyright
Copyright © 2012 the American Physiological Society
ISSN
0363-6119
eISSN
1522-1490
DOI
10.1152/ajpregu.00245.2011
pmid
22129615
Publisher site
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Abstract

Abstract Glucose metabolism increases in hypoxia and can be influenced by endogenous adenosine, but the role of adenosine for regulating glucose metabolism at rest or during exercise in hypoxia has not been elucidated in humans. We studied the effects of exogenous adenosine on human skeletal muscle glucose uptake and other blood energy substrates (free fatty acid (FFA) and lactate) by infusing adenosine into the femoral artery in nine healthy young men. The role of endogenous adenosine was studied by intra-arterial adenosine receptor inhibition (aminophylline) during dynamic one-leg knee extension exercise in normoxia and acute hypoxia corresponding to ∼3,400 m of altitude. Extraction and release of energy substrates were studied by arterial-to-venous (A-V) blood samples, and total uptake or release was determined by the product of A-V differences and muscle nutritive perfusion measured by positron emission tomography. The results showed that glucose uptake increased from a baseline value of 0.2 ± 0.2 to 2.0 ± 2.2 μmol·100 g −1 ·min −1 during adenosine infusion ( P < 0.05) at rest. Although acute hypoxia enhanced arterial FFA levels, it did not affect muscle substrate utilization at rest. During exercise, glucose uptake was higher (195%) during acute hypoxia compared with normoxia ( P = 0.058), and aminophylline had no effect on energy substrate utilization during exercise, despite that arterial FFA levels were increased. In conclusion, exogenous adenosine at rest and acute moderate hypoxia during low-intensity knee-extension exercise increases skeletal muscle glucose uptake, but the increase in hypoxia appears not to be mediated by adenosine. glucose uptake Copyright © 2012 the American Physiological Society « Previous Table of Contents This Article Published online before print November 2011 , doi: 10.​1152/​ajpregu.​00245.​2011 AJP - Regu Physiol February 2012 vol. 302 no. 3 R385-R390 » Abstract Free Full Text Free to you Full Text (PDF) Free to you All Versions of this Article: ajpregu.00245.2011v1 302/3/R385 most recent Classifications Physical Activity and Inactivity Obesity, Diabetes and Energy Homeostasis Services Email this article to a friend Alert me when this article is cited Alert me if a correction is posted Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Download to citation manager Citing Articles Load citing article information Citing articles via Web of Science Google Scholar Articles by Heinonen, I. Articles by Kalliokoski, K. K. PubMed PubMed citation Articles by Heinonen, I. Articles by Kalliokoski, K. K. Related Content Load related web page information Current Issue February 2012, 302 (3) Alert me to new issues of AJP - Regu Physiol About the Journal Information for Authors Submit a Manuscript Ethical Policies AuthorChoice PubMed Central Policy Reprints and Permissions Advertising Press Copyright © 2012 the American Physiological Society Print ISSN: 0363-6119 Online ISSN: 1522-1490 var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); var pageTracker = _gat._getTracker("UA-2924550-1"); pageTracker._trackPageview();

Journal

AJP - Regulatory, Integrative and Comparative Physiology – The American Physiological Society

Published: Feb 1, 2012

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