Document Detail

Effect of hyperthyroidism on the transport of pyruvate in rat-heart mitochondria.
MedLine Citation:
PMID:  2841978     Owner:  NLM     Status:  MEDLINE    
A comparative study of the transport of pyruvate in heart mitochondria from normal and triiodothyronine-treated rats has been carried out. It has been found that the rate of carrier-mediated (alpha-cyanocinnamate-sensitive) pyruvate uptake is significantly enhanced in mitochondria from triiodothyronine-treated rats as compared with mitochondria from control rats. The kinetic parameters of the pyruvate uptake indicate that only the Vmax of this process is enhanced whilst there is no change in the Km value. The enhanced rate of pyruvate uptake is not dependent on the increase of the transmembrane delta pH value (both mitochondria from normal and triiodothyronine-treated rats exhibit the same delta pH value) neither does it depend on the increase of the pyruvate carrier molecules (titration of these last with alpha-cyanocinnamate gives the same total number of binding sites). the pyruvate-dependent oxygen uptake is stimulated by 35-40% in mitochondria from hyperthyroid rats when compared with mitochondria from control rats. There is, however, no difference in either the respiratory control ratios or in the ADP/O ratios between these two types of mitochondria. The heart mitochondrial phospholipid composition is altered significantly in hyperthyroid rats; in particular, negatively charged phospholipid such as cardiolipin and phosphatidylserine were found to increase by more than 50%. Minor alterations were found in the pattern of fatty acids with an increase of 20:4/18:2 ratio. It is suggested that the changes in the kinetic parameters of pyruvate transport in mitochondria from hyperthyroid rats involve hormone-mediated changes in the lipid composition of the mitochondrial membranes which in turn modulate the activity of the pyruvate carrier.
G Paradies; F M Ruggiero
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  935     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  1988 Aug 
Date Detail:
Created Date:  1988-09-26     Completed Date:  1988-09-26     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  79-86     Citation Subset:  IM    
Department of Biochemistry and Molecular Biology, University of Bari, Italy.
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MeSH Terms
Biological Transport / drug effects
Carrier Proteins / metabolism
Cinnamates / metabolism
Fatty Acids / metabolism
Hydrogen-Ion Concentration
Hyperthyroidism / metabolism*,  physiopathology
Intracellular Membranes / metabolism
Membrane Transport Proteins*
Mitochondria, Heart / drug effects,  metabolism*
Monocarboxylic Acid Transporters
Phospholipids / metabolism
Pyruvates / metabolism*
Pyruvic Acid
Rats, Inbred Strains
Receptors, Cell Surface / analysis
Triiodothyronine / pharmacology
Reg. No./Substance:
0/Carrier Proteins; 0/Cinnamates; 0/Fatty Acids; 0/Membrane Transport Proteins; 0/Monocarboxylic Acid Transporters; 0/Phospholipids; 0/Pyruvates; 0/Receptors, Cell Surface; 0/pyruvate transport protein; 1011-92-3/alpha-cyanocinnamate; 127-17-3/Pyruvic Acid; 6893-02-3/Triiodothyronine

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

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