Document Detail

Triidothyronine and epinephrine rapidly modify myocardial substrate selection: a (13)C isotopomer analysis.
MedLine Citation:
PMID:  11595654     Owner:  NLM     Status:  MEDLINE    
Triiodothyronine (T(3)) exerts direct action on myocardial oxygen consumption (MVO(2)), although its immediate effects on substrate metabolism have not been elucidated. The hypothesis, that T(3) regulates substrate selection and flux, was tested in isovolumic rat hearts under four conditions: control, T(3) (10 nM), epinephrine (Epi), and T(3) and Epi (TE). Hearts were perfused with [1,3-(13)C]acetoacetic acid (AA, 0.17 mM), L-[3-(13)C]lactic acid (LAC, 1.2 mM), U-(13)C-labeled long-chain free fatty acids (FFA, 0.35 mM), and unlabeled D-glucose (5.5 mM) for 30 min. Fractional acetyl-CoA contribution to the tricarboxylic acid cycle (Fc) per substrate was determined using (13)C NMR and isotopomer analysis. Oxidative fluxes were calculated using Fc, the respiratory quotient, and MVO(2). T(3) increased (P < 0.05) Fc(FFA), decreased Fc(LAC), and increased absolute FFA oxidation from 0.58 +/- 0.03 to 0.68 +/- 0.03 micromol. min(-1). g dry wt(-1) (P < 0.05). Epi decreased Fc(FFA) and Fc(AA), although FFA flux increased from 0.58 +/- 0.03 to 0.75 +/- 0.09 micromol. min(-1). g dry wt(-1). T(3) moderated the change in Fc(FFA) induced by Epi. In summary, T(3) exerts direct action on substrate pathways and enhances FFA selection and oxidation, although the Epi effect dominates at a high work state.
J J Krueger; X H Ning; B M Argo; O Hyyti; M A Portman
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  American journal of physiology. Endocrinology and metabolism     Volume:  281     ISSN:  0193-1849     ISO Abbreviation:  Am. J. Physiol. Endocrinol. Metab.     Publication Date:  2001 Nov 
Date Detail:
Created Date:  2001-10-11     Completed Date:  2001-12-04     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  100901226     Medline TA:  Am J Physiol Endocrinol Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  E983-90     Citation Subset:  IM    
Division of Cardiology, Department of Pediatrics, University of Washington, School of Medicine, Seattle 98195, USA.
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MeSH Terms
Acetoacetates / administration & dosage,  metabolism
Acetyl Coenzyme A / metabolism
Citric Acid Cycle
Epinephrine / pharmacology*
Fatty Acids, Nonesterified / administration & dosage,  metabolism
Glucose / administration & dosage,  metabolism
Heart / drug effects
Lactic Acid / administration & dosage,  metabolism
Magnetic Resonance Spectroscopy
Myocardium / metabolism*
Oxygen Consumption / drug effects
Rats, Sprague-Dawley
Triiodothyronine / pharmacology*
Ventricular Function, Left / drug effects
Grant Support
Reg. No./Substance:
0/Acetoacetates; 0/Fatty Acids, Nonesterified; 50-21-5/Lactic Acid; 50-99-7/Glucose; 51-43-4/Epinephrine; 541-50-4/acetoacetic acid; 6893-02-3/Triiodothyronine; 72-89-9/Acetyl Coenzyme A

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

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