Myostatin, a negative regulator of muscle mass: implications for muscle degenerative diseases.

Myostatin is a secreted protein that negatively regulates skeletal muscle mass determining both muscle fiber number and size. The myostatin pathway is conserved and regulates muscle mass in a number of animal species ranging from fish to humans. Inhibition of myostatin using a variety of therapeutic approaches can increase muscle mass in a number of animal models of human disease, including muscular dystrophy.