Hepatokines as a molecular transducer of exercise

Exercise has health benefits and prevents a range of chronic diseases caused by physiological and biological changes in the whole body. Generally, the metabolic regulation of skeletal muscle through exercise is known to have a protective effect on the pathogenesis of metabolic syndrome, non-alcoholic fatty liver disease (NAFLD), type 2 diabetes (T2D), and cardiovascular disease (CVD). Besides this, the importance of the liver as an endocrine organ is a hot research topic. Hepatocytes also secrete many hepatokines in response to nutritional conditions and/or physical activity. In particular, certain hepatokines play a major role in the regulation of whole-body metabolic homeostasis. In this review, we summarize the recent research findings on the exercise-mediated regulation of hepatokines, including fibroblast growth factor 21, fetuin-A, angiopoietin-like protein 4, and follistatin. These hepatokines serve as molecular transducers of the metabolic benefits of physical activity in chronic metabolic diseases, including NAFLD, T2D, and CVDs, in various tissues.