Document Detail

Effects of plasma epinephrine on fat metabolism during exercise: interactions with exercise intensity.
MedLine Citation:
PMID:  10751201     Owner:  NLM     Status:  MEDLINE    
This study determined the effects of elevated plasma epinephrine on fat metabolism during exercise. On four occasions, seven moderately trained subjects cycled at 25% of peak oxygen consumption (VO(2 peak)) for 60 min. After 15 min of exercise, subjects were intravenously infused with low (0.96 +/- 0.10 nM), moderate (1.92 +/- 0.24 nM), or high (3.44 +/- 0.50 nM) levels (all P < 0.05) of epinephrine to increase plasma epinephrine above control (Con; 0.59 +/- 0.10 nM). During the interval between 35 and 55 min of exercise, lipolysis [i.e., rate of appearance of glycerol] increased above Con (4.9 +/- 0.5 micromol. kg(-1). min(-1)) with low, moderate, and high (6.5 +/- 0.5, 7.1 +/- 0.8, and 10.6 +/- 1.2 micromol. kg(-1). min(-1), respectively; all P < 0.05) levels of epinephrine despite simultaneous increases in plasma insulin. The release of fatty acid into plasma also increased progressively with the graded epinephrine infusions. However, fatty acid oxidation was lower than Con (11.1 +/- 0.8 micromol. kg(-1). min(-1)) during moderate and high levels (8.7 +/- 0.7 and 8.1 +/- 0.9 micromol. kg(-1). min(-1), respectively; P < 0.05). In one additional trial, the same subjects exercised at 45% VO(2 peak) without epinephrine infusion, which produced a plasma epinephrine concentration identical to low levels. However, lipolysis was lower (i.e., 5.5 +/- 0.6 vs. 6.5 +/- 0.5 micromol. kg(-1). min(-1); P < 0.05). In conclusion, elevations in plasma epinephrine concentration during exercise at 25% of VO(2 peak) progressively increase whole body lipolysis but decrease fatty acid oxidation. Last, increasing exercise intensity from 25 to 45% VO(2 peak) attenuates the lipolytic actions of epinephrine.
R Mora-Rodriguez; E F Coyle
Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  American journal of physiology. Endocrinology and metabolism     Volume:  278     ISSN:  0193-1849     ISO Abbreviation:  Am. J. Physiol. Endocrinol. Metab.     Publication Date:  2000 Apr 
Date Detail:
Created Date:  2000-05-01     Completed Date:  2000-05-01     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  100901226     Medline TA:  Am J Physiol Endocrinol Metab     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  E669-76     Citation Subset:  IM; S    
University of Castilla-la Mancha at Toledo, Toledo 45071, Spain.
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MeSH Terms
Epinephrine / administration & dosage,  blood*,  pharmacology
Exercise / physiology*
Fatty Acids / metabolism
Fatty Acids, Nonesterified / blood
Glycerol / blood
Infusions, Intravenous
Insulin / blood
Lipid Metabolism*
Lipolysis / physiology
Norepinephrine / blood
Oxygen Consumption / drug effects,  physiology
Pulmonary Gas Exchange / drug effects,  physiology
Reg. No./Substance:
0/Fatty Acids; 0/Fatty Acids, Nonesterified; 11061-68-0/Insulin; 51-41-2/Norepinephrine; 51-43-4/Epinephrine; 56-81-5/Glycerol

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