Document Detail

Hormone regulation of cardiac energy metabolism. I. Creatine transport across cell membranes of euthyroid and hyperthyroid rat heart.
MedLine Citation:
PMID:  4096715     Owner:  NLM     Status:  MEDLINE    
Hyperthyroid rat heart was studied with the purpose of identifying the mechanism for the significant decrease in total creatine (free creatine plus phosphocreatine) observed in this pathology and its consequences on heart function. Administration of L-thyroxine in doses of 50-100 micrograms/100 g of body weight during a week resulted in a reversible decrease of the total creatine by 40-50%. Simultaneously, remarkable changes in the creatine transport system across the cardiac cell membranes were observed: both the maximal rate of its active uptake and its passive movement along its concentration gradient were enhanced. In euthyroid hearts, the parameters of creatine uptake (Km approximately or equal to 0.05 mM, Vmax = 20 nmole/min/g dry weight) were similar to those for skeletal muscle and the passive movement of creatine was negligible. In hyperthyroid hearts the latter rate was enhanced to 0.4 mumole min/g dry weight, this showing reversible damages in the cell membrane structure induced by L-thyroxine. This conclusion is consistent with observed penetration of colloidal lanthanum into the cells of hyperthyroid hearts. Perfusion of hyperthyroid rat hearts with 50 mM creatine significantly restored creatine content in the cells, Hyperthyroid hearts with decreased creatine content were found to develop ischemic contracture more rapidly and in higher extent than the euthyroid hearts. Increased sensitivity to ischemic damage may be related to decreased efficiency of energy channeling via phosphocreatine pathway.
E K Seppet; A J Adoyaan; A P Kallikorm; G B Chernousova; N V Lyulina; V G Sharov; V V Severin; M I Popovich; V A Saks
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Biochemical medicine     Volume:  34     ISSN:  0006-2944     ISO Abbreviation:  Biochem Med     Publication Date:  1985 Dec 
Date Detail:
Created Date:  1986-03-31     Completed Date:  1986-03-31     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0151424     Medline TA:  Biochem Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  267-79     Citation Subset:  IM    
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MeSH Terms
Cell Membrane / metabolism
Coronary Disease / metabolism
Creatine / metabolism*
Energy Metabolism*
Hyperthyroidism / metabolism*
Myocardial Contraction / drug effects
Myocardium / metabolism*
Phosphocreatine / metabolism
Rats, Inbred Strains
Thyroid Hormones / physiology*
Thyroxine / pharmacology
Time Factors
Reg. No./Substance:
0/Thyroid Hormones; 57-00-1/Creatine; 67-07-2/Phosphocreatine; 7488-70-2/Thyroxine

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

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