Document Detail

beta-Agonist stimulation produces changes in cardiac AMPK and coronary lumen LPL only during increased workload.
MedLine Citation:
PMID:  15687106     Owner:  NLM     Status:  MEDLINE    
Given the importance of lipoprotein lipase (LPL) in cardiac and vascular pathology, the objective of the present study was to investigate whether the beta-agonist isoproterenol (Iso) influences cardiac LPL. Incubation of quiescent cardiomyocytes with Iso for 60 min had no effect on basal, intracellular, or heparin-releasable (HR)-LPL activity. Similarly, Iso did not change HR-LPL in Langendorff isolated hearts that do not beat against an afterload. In the intact animal, LPL activity at the vascular lumen increased significantly in the Iso-treated group, together with a substantial increase in rate-pressure product. This LPL increase was likely via mechanisms regulated by activation of AMP-activated protein kinase (AMPK) and inactivation of acetyl-CoA carboxylase (ACC280). In glucose-perfused hearts, simply switching from Langendorff to the isolated working heart (that beats against an afterload) induced increases in AMPK and ACC280 phosphorylation and enhanced HR-LPL activity. Provision of insulin and albumin-bound palmitic acid to the working heart was able to reverse these effects. In these hearts, introduction of Iso to the buffer perfusate duplicated the effects seen when this beta-agonist was given in vivo. Our data suggest that Iso can influence HR-LPL only during conditions of increased workload, mechanical performance and excessive energy expenditure, and likely in an AMPK-dependent manner.
Ding An; Girsh Kewalramani; Dake Qi; Thomas Pulinilkunnil; Sanjoy Ghosh; Ashraf Abrahani; Rich Wambolt; Michael Allard; Sheila M Innis; Brian Rodrigues
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't     Date:  2005-02-01
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 Jun 
Date Detail:
Created Date:  2005-05-10     Completed Date:  2005-06-16     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:  E1120-7     Citation Subset:  IM    
Faculty of Pharmaceutical Sciences, The Univ. of British Columbia, 2146 East Mall, Vancouver, BC, Canada V6T 1Z3.
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MeSH Terms
AMP-Activated Protein Kinases
Acetyl-CoA Carboxylase / metabolism
Adrenergic beta-Agonists / pharmacology*
Blotting, Western
Endothelium, Vascular / metabolism
Heart / drug effects*,  physiology
Isoproterenol / pharmacology*
Lipoprotein Lipase / genetics,  metabolism*
Multienzyme Complexes / metabolism*
Myocardial Contraction / drug effects,  physiology
Myocardium / enzymology*
Myocytes, Cardiac / enzymology
Physical Conditioning, Animal / physiology
Protein-Serine-Threonine Kinases / metabolism*
RNA / chemistry,  genetics
Rats, Wistar
Reverse Transcriptase Polymerase Chain Reaction
Stimulation, Chemical
Reg. No./Substance:
0/Adrenergic beta-Agonists; 0/Multienzyme Complexes; 63231-63-0/RNA; 7683-59-2/Isoproterenol; EC Protein Kinases; EC Kinases; EC Lipase; EC Carboxylase

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

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