Fig. 3. Effects of glucagon-like peptide-1 (GLP-1) on the osteogenic differentiation of adipose-derived stem cells (ADSCs). The ADSCs were cultured osteogenic induction medium (OIM) treated with various concentration of GLP-1 (0, 10 nM and 100 nM). The media containing GLP-1 was renewed every day. (A) The mRNA level of alkaline phosphatase (ALP) was determined by real time polymerase chain reaction (PCR) and it was normalized by the expression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). ^*P < 0.05 (vs. OIM). (B, C) On day 10, ALP activity was measured by ALP staining and enzyme-linked immunosorbent assay (ELISA). ALP was indicated by the red staining. Original magnification, × 100. ALP activity was determined using a colorimetric end point assay measuring the enzyme p-nitrophenol (pNP) in the presence of ALP. (D) On day 14, cells were stained with alizarin red S and calcium deposition nodules were stained as dark red areas. Original magnification, × 100. (E) Bar graph shows quantitative results of (D). ^†P < 0.05 (vs. OIM).