Document Detail

Thyroid hormone control of Na+-K+-ATPase and K+-dependent phosphatase in rat heart.
MedLine Citation:
PMID:  193406     Owner:  NLM     Status:  MEDLINE    
To assess the possible role of the Na+ pump in mediating physiological responses to thyroid hormone in the rat myocardium, we examined the effects of L-3,5,3'-triiodothyronine (T3) on the activities of the closely associated enzymes, Na+-K+-dependent adenosine triphosphatase (Na-K-ATPase) and K+-dependent p-nitrophenyl phosphatase (K-dep-pNPPase). In hypothyroid rats, administration of T3 (50 microng/100 g body wt) resulted in significant increases (greater than 50%) in Na-K-ATPase and K-dep-pNPPase activities in both crude homogenates and microsomal fractions of the rat ventricle. Significant effects on Na-K-ATPase activity were also attained with low doses (1 microng/100 g body wt) of T3. A method was developed for assaying K-dep-pNPPase activity in cardiac slices. With this technique, enhancement in K-dep-pNPPase activity of 89.2% was found in ventricle slices after treatment of hypothyroid rats with T3 (50 microng/100 g body wt), implying that augmentation of the capacity of the Na+ pump is achieved in vivo. The potent analogue, L-3,5-diiodo-3' isopropyl thyronine (isopropyl T2) had the same effects on cardiac growth and Na-K-ATPase as T3, in hypothyroid rats. In contrast, the relatively inactive isomer, L-3,3',5'-triiodothyronine (reverse T3) had no significant effect on the heart weight-to-body weight ratio or on ventricular Na-K-ATPase activity.
K D Philipson; I S Edelman
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  232     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1977 May 
Date Detail:
Created Date:  1977-06-30     Completed Date:  1977-06-30     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  C196-201     Citation Subset:  IM    
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MeSH Terms
4-Nitrophenylphosphatase / metabolism*
Adenosine Triphosphatases / metabolism*
Biological Transport, Active / drug effects
Hypothyroidism / enzymology
Microsomes / enzymology
Myocardium / enzymology*,  ultrastructure
Phosphoric Monoester Hydrolases / metabolism*
Sodium / metabolism
Structure-Activity Relationship
Thyronines / analogs & derivatives,  pharmacology
Triiodothyronine / pharmacology*
Reg. No./Substance:
0/Thyronines; 6893-02-3/Triiodothyronine; 7440-23-5/Sodium; EC 3.1.3.-/Phosphoric Monoester Hydrolases; EC; EC 3.6.1.-/Adenosine Triphosphatases

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

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