Document Detail


Cardiac physiology, biochemistry and morphology in response to excess growth hormone in the rat.
MedLine Citation:
PMID:  2143788     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The cardiac effects of excess growth hormone (GH) were studied in the intact adult rat and in tissues prepared from the rat. Female Wistar-Furth rats were inoculated with a clonal cell line of pituitary cells which secrete GH. Five weeks later, heart weight had increased 37% compared to control (P less than 0.01) due to concomitant increases in left and right ventricular weight. Hemodynamic measurements in the anesthetized rat showed that GH stimulated rats had a decrease in blood pressure and heart rate and a small increase of left ventricular end-diastolic pressure (P less than 0.05). Measurement of left ventricular contractility and relaxation, and response to beta-adrenergic stimulation were decreased in GH compared to control (P less than 0.05). Contractile protein biochemistry showed an 18% reduction in Ca2(+)-myosin ATPase activity of the left ventricle (P less than 0.05) and non-denaturing pyrophosphate gels of purified myosin demonstrated a significant shift of isoforms from the exclusive V1 pattern to both V1 and V3 isomyosins in both ventricles (P less than 0.05). In contrast to the physiological and protein biochemistry adaptations, left ventricular morphology by light microscopy and ultrastructure by electron microscopy were normal in the GH stimulated heart. There were no significant changes in myofibril fraction, in the myofibril to mitochondria ratio or in the capillary numerical density of the hypertrophied left ventricle (P = N.S.). This study demonstrates that under prolonged and extreme stimulation by GH, the heart undergoes considerable growth/hypertrophy. Although cardiac morphology remains normal during this growth, there are alterations of the isomyosins such that ATPase activity is diminished and ventricular function is decreased.
Authors:
S A Rubin; P Buttrick; A Malhotra; S Melmed; M C Fishbein
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of molecular and cellular cardiology     Volume:  22     ISSN:  0022-2828     ISO Abbreviation:  J. Mol. Cell. Cardiol.     Publication Date:  1990 Apr 
Date Detail:
Created Date:  1990-09-25     Completed Date:  1990-09-25     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  0262322     Medline TA:  J Mol Cell Cardiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  429-38     Citation Subset:  IM    
Affiliation:
Division of Cardiology, Cedars-Sinai Medical Center, Los Angeles, CA 90048.
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MeSH Terms
Descriptor/Qualifier:
Animals
Calcium-Transporting ATPases / metabolism
Cardiomegaly / metabolism,  pathology*
Cell Line
Female
Growth Hormone / blood,  pharmacology*
Heart / physiology
Hematocrit
Hemodynamics
Myocardial Contraction / drug effects
Myocardium / ultrastructure*
Myosins / metabolism
Rats
Rats, Inbred Strains
Chemical
Reg. No./Substance:
9002-72-6/Growth Hormone; EC 3.6.1.8/Calcium-Transporting ATPases; EC 3.6.4.1/Myosins

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


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