Time Course Alteration of Endothelin-1 Gene Expression in the Heart during Exercise and Recovery from Post-exercise Periods in Rats

Endothelin-1 (ET-1) is produced by endothelial cells and cardiac myocytes. ET-1 has potent positive inotropic and chronotropic effects in the heart and causes myocardial cell hypertrophy. We investigated the alteration of gene expression of ET-1 in the heart of rats during acute exercise and 24 hour postexercise periods. Sprague-Dawley rats performed treadmill running for 30 minutes at a speed of 30 m/minute. We determined the expression of preproendothelin-1 mRNA in the rat hearts of resting (control) and 0, 0.5, 1, 3, 6, 12, and 24 hour post-exercise time points, respectively. The percent changes in expression of preproendothelin-1 mRNA in the heart from resting control rats were significantly increased at the time point of 1 hour post-exercise (199.0 ± 33.6%, P< 0.05), and this enhancement returned to the level of resting control rats at the time points of 6, 12, and 24 hours post-exercise. These results suggest that a bout of exercise causes time-related enhancement of gene expression of ET-1 in the rat hearts during acute exercise and 24 hour post-exercise periods. Therefore, an exercise-induced change of ET-1 gene expression in the heart may participate in mechanisms of exercise-induced and/or training-induced adaptive responses of the heart.