Fig. 2.

Tissue target functions of FGF21. FGF21, like FGF19, is a hormone that acts to alter a vast array of metabolic processes in an endocrine and autocrine manner. In the liver, FGF21 regulates carbohydrate and lipid metabolism. In adipose tissue, FGF21 induces thermogenesis and browning of WAT. FGF21 indirectly increases insulin synthesis in the pancreas. The hormone effects of FGF21 improve metabolic function, not only by promoting insulin sensitivity, but also reducing body weight by acting on the brain to decrease food intake and increase energy expenditure.