TGF-ß1 and prepro-ANP mRNAs are differentially regulated in exercise-induced cardiac hypertrophy.
Calderone, Angelino, René J. L. Murphy, Julie Lavoie, Federico Colombo, and Louise Béliveau.
1Centre de Recherche de l'Institut de Cardiologie de Montréal and Département de Physiologie, and 3Département de Kinésiologie, Université de Montréal, Montreal, Quebec, Canada H1T 1C8; and 2School of Recreation Management and Kinesiology, Acadia University, Acadia, Nova Scotia, Canada
APStracts 8:0280A, 2001.
The induction of transforming growth factor (TGF)-ß and prepro-atrial natriuretic peptide (ANP) mRNAs represents hallmark features of pathological cardiac hypertrophy. The present study examined whether this pattern of mRNA expression was conserved in a physiological model of cardiac hypertrophy. To address this thesis, female Sprague-Dawley rats were individually housed and permitted to run freely. Voluntary exercise for 3 and 6 wk resulted in biventricular hypertrophy and increased cytochrome c oxidase activity in the triceps muscle. In the hypertrophied left ventricle, the steady-state mRNA level of the cardiac fetal gene prepro-ANP and the extracellular matrix proteins preprocollagen-a1 and fibronectin were similar in exercise-trained and sedentary rats. By contrast, an increased expression of TGF-ß1 mRNA was observed, whereas TGF-ß3 mRNA level was unchanged in the hypertrophied left ventricle of exercise-trained compared with sedentary rats. These data highlight a heterogeneity in the regulation of TGF-ß isoforms, and the increased expression of ventricular TGF-ß1 mRNA in physiological cardiac hypertrophy may contribute to myocardial remodeling.
Received 19 January 2000; accepted in final form 13 March 2001
APS Manuscript Number A48-0.
Article publication pending J Appl Physiol
ISSN 1080-4757 Copyright 2001 The American Physiological Society.
Published in APStracts on 18 June 2001