[Homeostasis and Disorder of Musculoskeletal System.Roles of the motor system in systemic metabolism and the aging-related disorders.]

Among the tissues involved in the motor system, skeletal muscle plays an important role in systemic metabolism and is the largest organ in terms of glucose uptake. Insulin promotes anabolism of nutrients in skeletal muscle, as in other insulin-targeted organs, and maintains muscle volume, in cooperation with insulin-like growth factor-1. In humans, along with aging, insulin resistance is induced in skeletal muscle, which could lead to systemic insulin resistance, and circulating IGF-1 levels are lowered. These changes contribute to the development of sarcopenia, in which function and volume of skeletal muscle are impaired, and modulation of the insulin/IGF-1 signaling could be promising in treatment of sarcopenia.