Background In recent years, skeletal muscle has been recognized not only as a locomotor organ but also as a secretory organ. The bioactive molecules it releases, known as myokines, act on distant organs through the circulation and locally on muscle tissue. Previously, we identified R-spondin 3 (Rspo3) as a Type I fiber-specific myokine that promotes myoblast differentiation into Type I fibers in vitro. In this study, we furthe...

Background Myofibers are broadly classified as slow-twitch (Type I) and fast-twitch (Type II) fibers. These two types of myofibers coexist within the same skeletal muscle tissue, determining the contractile and metabolic properties of skeletal muscle tissue by fiber type distribution. Methods and results By examining each fiber type separately, we confirmed that brain-derived neurotrophic factor (BDNF) gene is highly expressed...