Fibroblast growth factor-21 (FGF-21) belongs to the large FGF family which is encoded by the FGF-21 gene and it is specifically induced by HMGCS2 activity. All FGF family members are heparin binding growth factors with a core 120 amino acid (a.a.) FGF domain that allows for a common tertiary structure and they are involved in a variety of biological processes including embryonic development, cell growth, morphogenesis, tissue repair, tumor growth and invasion. FGF-21 stimulates glucose uptake in differentiated adipocytes via the induction of glucose transporter SLC2A1/GLUT1 expression (but not SLC2A4/GLUT4 expression) and the activity depends on the presence of KLB. FGF-21 contains a 28 a.a. signal sequence and a 181 a.a. mature region but show limited binding to heparin. In addition, Mature human FGF-21 respectively shows 81 % a.a. identity to murine and rat FGF-21, and is known to be active on murine cells.