Document Detail


Regulation of glucose kinetics during intense exercise in humans: effects of alpha- and beta-adrenergic blockade.
MedLine Citation:
PMID:  14669166     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study examined the effect of combined alpha- and beta-adrenergic blockade on glucose kinetics during intense exercise. Six endurance-trained men exercised for 20 minutes at approximately 78% of their peak oxygen consumption (Vo(2)) following ingestion of a placebo (CON) or combined alpha- (prazosin hydrochloride) and beta- (timolol maleate) adrenoceptor antagonists (BLK). Plasma glucose increased during exercise in CON (0 minutes: 5.5 +/- 0.1; 20 minutes: 6.5 +/- 0.3 mmol. L(-1), P <.05). In BLK, the exercise-induced increase in plasma glucose was abolished (0 minutes: 5.7 +/- 0.3; 20 minutes: 5.7 +/- 0.1 mmol. L(-1)). Glucose kinetics were measured using a primed, continuous infusion of [6,6-(2)H] glucose. Glucose production was not different between trials; on average these values were 25.3 +/- 3.9 and 30.9 +/- 4.4 micromol. kg(-1). min(-1) in CON and BLK, respectively. Glucose uptake during exercise was greater (P <.05) in BLK (30.6 +/- 4.6 micromol. kg(-1). min(-1)) compared with CON (18.4 +/- 2.5 micromol. kg(-1). min(-1)). In BLK, plasma insulin and catecholamines were higher (P <.05), while plasma glucagon was unchanged from CON. Free fatty acids (FFA) and glycerol were lower (P <.05) in BLK. These findings demonstrate that adrenergic blockade during intense exercise results in a blunted plasma glucose response that is due to enhanced glucose uptake, with no significant change in glucose production.
Authors:
Kirsten F Howlett; Matthew J Watt; Mark Hargreaves; Mark A Febbraio
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Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Metabolism: clinical and experimental     Volume:  52     ISSN:  0026-0495     ISO Abbreviation:  Metab. Clin. Exp.     Publication Date:  2003 Dec 
Date Detail:
Created Date:  2003-12-11     Completed Date:  2004-02-06     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0375267     Medline TA:  Metabolism     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1615-20     Citation Subset:  IM    
Affiliation:
Exercise, Muscle and Metabolism Unit, School of Health Sciences, Deakin University, Burwood, Australia.
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MeSH Terms
Descriptor/Qualifier:
Adrenergic alpha-Antagonists / pharmacology*
Adrenergic beta-Antagonists / pharmacology*
Adult
Anaerobic Threshold / physiology
Blood Glucose / metabolism
Epinephrine / blood
Exercise / physiology*
Exercise Test
Fatty Acids, Nonesterified / blood
Glucose / metabolism*,  pharmacology
Hemodynamics / physiology
Hormones / blood
Humans
Kinetics
Lactic Acid / blood
Male
Norepinephrine / blood
Oxygen Consumption / physiology
Prazosin / pharmacology
Respiratory Mechanics / physiology
Timolol / pharmacology
Chemical
Reg. No./Substance:
0/Adrenergic alpha-Antagonists; 0/Adrenergic beta-Antagonists; 0/Blood Glucose; 0/Fatty Acids, Nonesterified; 0/Hormones; 19216-56-9/Prazosin; 26839-75-8/Timolol; 50-21-5/Lactic Acid; 50-99-7/Glucose; 51-41-2/Norepinephrine; 51-43-4/Epinephrine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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