Fibroblast growth factor 21 (FGF21), which stimulates glucose uptake in differentiated adipocytes via the induction of glucose transporter SLC2A1/GLUT1 expression. FGF21 has been shown to protect animals from diet-induced obesity when overexpressed in transgenic mice. It also lowers blood glucose and triglyceride levels when administered to diabetic rodents, suggesting it may exhibit the therapeutic characteristics necessary for effective treatment of diabetes. Treatment of animals with FGF21 results in increased energy expenditure, fat utilisation and lipid excretion. FGF21 is most abundantly expressed in the liver, and also expressed in the thymus at lower levels.