Myosin isozyme changes in the heart following constriction of the ascending aorta of a 25-day old rat.

When a constricting band is placed around the ascending aorta of young (25-day old) rats, all chambers of the heart eventually produce hypertrophy. Both the left and right ventricles show strong shifts toward an isozyme pattern in which V3 is predominant, similar to that seen in models where hypertrophy is induced in adult rats. The hypertrophied atria however, show no detectable change in the native myosin isozymes or the light chain subunits.