Stretch, a Common Denominator in Muscle Growth

Abstract

Increased mechanical work leads to hypertrophy of muscle cells and hyperplasia of non-muscle cells in heart and skeletal muscle. Greater work accelerates energy production via anaerobic glycolysis and oxidative metabolism, elevates oxygen consumption, increases muscle blood flow, and raises protein synthetic rate. The mechanical parameter(s) most closely associated with faster protein synthesis in both heart and skeletal muscle is stretch. Our laboratory has studied the relationship between stretch of the ventricular wall induced by increased aortic pressure and elevated intraventricular pressure and rates of protein synthesis and degradation in heart muscle. The purpose of these studies is to understand the molecular mechanism(s) of cardiac hypertrophy induced by greater afterload or preload.