Cell differentiation
3T3-L1 cells were differentiated into adipocytes using 10 µg/mL insulin, 1µM dexamethasone, and 0.5 mM isobuthyl-methylxanthine (Sigma-Aldrich Co., St. Lousi, MO, USA) for 2 days followed by incubation for 2 days with DMEM containing insulin (10 µg/mL). C2C12 cells were differentiated using 90% DMEM, 2% horse serum (HS; WELGENE, Daegu, Korea), and 100 unit/mL P/S for 4 days. Differentiation was observed and confirmed with inverted microscope (Carl Zeiss, Gottingen, Germany) at 200x.