Document Detail


Morphometric and biochemical characteristics of ventricular hypertrophy in male rainbow trout (Oncorhynchus mykiss).
MedLine Citation:
PMID:  9556537     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We examined the morphometric and biochemical effects of ventricular hypertrophy in male rainbow trout (Oncorhynchus mykiss) during sexual maturation. Our investigation focused on characterizing the growth of ventricular layers, on cardiomyocyte dimensions (length, cross-sectional area and cell volume) and on the activities of enzymes involved in intermediary metabolism. Relative ventricle mass (100 x ventricle mass/body mass) increased by as much as 2.4-fold during sexual maturation [as defined by an increasing gonadosomatic index (100 x gonad mass/body mass)], and this resulted in an increased proportion of epicardium relative to endocardium. Ventricular enlargement was associated with increased length (+31 %) and transverse cross-sectional area (+83 %) of cardiomyocytes, which resulted in an expansion of up to 2.2-fold in mean myocyte volume (from 1233 to 2751 micron3). These results indicate that sexual maturation induces ventricular enlargement through myocyte hypertrophy. Cell length and cross-sectional area were similar in both myocardial layers, and myocytes were elliptical rather than circular in transverse cross section. Ventricular hypertrophy did not alter transverse cell shape, perhaps reflecting the maintenance of short diffusion distances for small molecules as cells hypertrophy. Myocyte hypertrophy could not account entirely for the sevenfold range of ventricle masses from different-sized fish, indicating that myocyte hyperplasia contributes substantially to ventricular growth as trout grow. Measurements of the maximal activities of metabolic enzymes demonstrated that ventricular hypertrophy was associated with (1) higher epicardial but not endocardial activities of citrate synthase (by 23 %) and beta-hydroxyacyl-CoA dehydrogenase (by 20 %); (2) lower activities of hexokinase (by 50 %) in both layers, and (3) no change in lactate dehydrogenase or pyruvate kinase activities, which were also similar between layers. These results suggest that the energetic needs of the hypertrophied trout ventricle may be met through increased reliance on fatty acid oxidation, particularly by the endocardium, but decreased reliance on glucose as a metabolic fuel in both layers.
Authors:
R J Clark; K J Rodnick
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of experimental biology     Volume:  201     ISSN:  0022-0949     ISO Abbreviation:  J. Exp. Biol.     Publication Date:  1998 May 
Date Detail:
Created Date:  1999-01-06     Completed Date:  1999-01-06     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0243705     Medline TA:  J Exp Biol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  1541-52     Citation Subset:  IM    
Affiliation:
Department of Biological Sciences, Idaho State University, Pocatello, ID 83209-8007, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Body Weight
Cardiomegaly / enzymology,  metabolism*,  pathology*,  physiopathology
Heart Ventricles / chemistry,  enzymology,  pathology,  physiopathology
Hyperplasia
Male
Myocardium / chemistry,  enzymology,  pathology
Oncorhynchus mykiss
Organ Size
Sexual Maturation

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


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