[Body weight and bone/calcium metabolism. Muscle, myokines and bone/calcium metabolism.]

The interactions between skeletal muscle and bone have been noted, and muscle influences bone metabolism by secreting myokines. Myostatin is known as a myostatic factor through an inhibition of Smad2/3 signaling in muscle. It is involved in the pathophysiology of rheumatoid arthritis via a stimulation of bone resorption. Follistatin might be involved in the regulation of muscle and bone by gravity change through an attenuation of myostatin action. Irisin with energy metabolism improvement actions is related to the effects of mechanical stress or exercise on muscle and bone. The research of myokines might lead to the improvement of clinical practice of sarcopenia and osteoporosis.