Fibroblast growth factor-21 (FGF-21) belongs to the large FGF family and it is specifically induced by HMGCS2 activity. In mice, brown adipose tissue becomes a source of systemic FGF21 after cold exposure. 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, in the presence of betaKlotho as a protein cofactor, signals through the FGFR 1c and 4 receptors. Recombinant murine FGF-21 contains 182 amino acids residues and show limited binding to heparin. In addition, Murine FGF-21 respectively shows 81 % and 92 % a.a. identity to human and rat FGF-21, and it show activity on human and rat cells.