Document Detail


AMPK activation is not critical in the regulation of muscle FA uptake and oxidation during low-intensity muscle contraction.
MedLine Citation:
PMID:  15547141     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
To determine the role of AMP-activated protein kinase (AMPK) activation on the regulation of fatty acid (FA) uptake and oxidation, we perfused rat hindquarters with 6 mM glucose, 10 microU/ml insulin, 550 microM palmitate, and [14C]palmitate during rest (R) or electrical stimulation (ES), inducing low-intensity (0.1 Hz) muscle contraction either with or without 2 mM 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR). AICAR treatment significantly increased glucose and FA uptake during R (P < 0.05) but had no effect on either variable during ES (P > 0.05). AICAR treatment significantly increased total FA oxidation (P < 0.05) during both R (0.38 +/- 0.11 vs. 0.89 +/- 0.1 nmol x min(-1) x g(-1)) and ES (0.73 +/- 0.11 vs. 2.01 +/- 0.1 nmol x min(-1) x g(-1)), which was paralleled in both conditions by a significant increase and significant decrease in AMPK and acetyl-CoA carboxylase (ACC) activity, respectively (P < 0.05). Low-intensity muscle contraction increased glucose uptake, FA uptake, and total FA oxidation (P < 0.05) despite no change in AMPK (950.5 +/- 35.9 vs. 1,067.7 +/- 58.8 nmol x min(-1) x g(-1)) or ACC (51.2 +/- 6.7 vs. 55.7 +/- 2.0 nmol x min(-1) x g(-1)) activity from R to ES (P > 0.05). When contraction and AICAR treatment were combined, the AICAR-induced increase in AMPK activity (34%) did not account for the synergistic increase in FA oxidation (175%) observed under similar conditions. These results suggest that while AMPK-dependent mechanisms may regulate FA uptake and FA oxidation at rest, AMPK-independent mechanisms predominate during low-intensity muscle contraction.
Authors:
Marcella A Raney; Alice J Yee; Mark K Todd; Lorraine P Turcotte
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.     Date:  2004-11-16
Journal Detail:
Title:  American journal of physiology. Endocrinology and metabolism     Volume:  288     ISSN:  0193-1849     ISO Abbreviation:  Am. J. Physiol. Endocrinol. Metab.     Publication Date:  2005 Mar 
Date Detail:
Created Date:  2005-02-07     Completed Date:  2005-04-26     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100901226     Medline TA:  Am J Physiol Endocrinol Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  E592-8     Citation Subset:  IM    
Affiliation:
Dept. of Kinesiology and Biological Sciences, Diabetes Research Center, Univ. of Southern California, 3560 Watt Way, PED 107, Los Angeles, CA 90089-0652, USA.
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MeSH Terms
Descriptor/Qualifier:
AMP-Activated Protein Kinases
Acetyl-CoA Carboxylase / metabolism
Aminoimidazole Carboxamide / analogs & derivatives*,  pharmacology
Animals
Electric Stimulation
Enzyme Activation
Fatty Acids / metabolism*,  pharmacokinetics
Glucose / metabolism,  pharmacology
Hypoglycemic Agents / pharmacology
Lactic Acid / metabolism,  pharmacology
Male
Malonyl Coenzyme A / metabolism
Multienzyme Complexes / metabolism*
Muscle Contraction / physiology*
Muscle, Skeletal / drug effects,  metabolism,  physiology*
Oxidation-Reduction
Oxygen Consumption / physiology
Palmitic Acid / metabolism,  pharmacology
Protein-Serine-Threonine Kinases / metabolism*
Rats
Rats, Wistar
Ribonucleotides / pharmacology
Grant Support
ID/Acronym/Agency:
AR-45168/AR/NIAMS NIH HHS
Chemical
Reg. No./Substance:
0/Fatty Acids; 0/Hypoglycemic Agents; 0/Multienzyme Complexes; 0/Ribonucleotides; 3031-94-5/AICA ribonucleotide; 360-97-4/Aminoimidazole Carboxamide; 50-21-5/Lactic Acid; 50-99-7/Glucose; 524-14-1/Malonyl Coenzyme A; 57-10-3/Palmitic Acid; EC 2.7.11.1/AMP-Activated Protein Kinases; EC 2.7.11.1/Protein-Serine-Threonine Kinases; EC 6.4.1.2/Acetyl-CoA Carboxylase

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


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