Decarboxylated osteocalcin, a possible drug for type 2 diabetes, triggers glucose uptake in MG63 cells

Figure 4 Promotional effect of decarboxylated osteocalcin on glucose uptake after long-term stimulation (72 h) in MG63 cells. A: Protein bands; B: Relative protein levels of GPRC6A (G protein-coupled receptor family C group 6 subtype A), p-Akt (Ser473)/Akt, hypoxia-inducible factor 1 alpha (HIF-1α), glucose transporter 1 (GLUT1), and Runx2 after decarboxylated osteocalcin (dcOC) stimulation for 72 h at different concentrations; C: Protein bands; D: Relative protein levels of HIF-1α and GLUT1; E: The distribution of fluorescence intensities which represented 2-Deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]-D-glucose (2-NBDG) uptake; F: The normalized fluorescence intensity corresponding to 2-NBDG uptake. The MG63 cells in C-F were treated with dcOC (10 ng/mL) 72 h and (or) were transfected with HIF-1α siRNA. The data are representative of three independent experiments performed in triplicate. B: ^aP < 0.05, ^bP < 0.01 vs untreated cells; D and F: ^aP < 0.05, ^bP < 0.01 vs the control group; ^cP < 0.05, ^dP < 0.01 vs the dcOC-only group. dcOC: Decarboxylated osteocalcin; HIF-1α: Hypoxia-inducible factor 1 alpha; GLUT1: Glucose transporter 1; GPRC6A: G protein-coupled receptor family C group 6 subtype A.