The G-protein-coupled receptor APJ and its endogenous ligand apelin are widely expressed in many peripheral tissues and central nervous system, including adipose tissue, skeletal muscles and hypothalamus. Apelin/APJ system, involved in numerous physiological functions like angiogenesis, fluid homeostasis and energy metabolism regulation, is notably implicated in the development of different pathologies such as diabetes and its complications. Increasing evidence suggests that apelin regulates insulin sensitivity, stimulates glucose utilization and enhances brown adipogenesis in different tissue...