Effects of SSE on phosphorylation of the MAPK family proteins in 3T3-L1 adipocytes. (a) 3T3-L1 preadipocytes were differentiated into adipocytes by incubation with isobutylmethylxanthine, dexamethasone, and insulin (MDI) for 4 days. The cells were exposed to various concentrations of SSE (0, 25, 50, 100, 200, or 400 μg/mL) during the differentiation period. Cell lysates were prepared and subjected to immunoblotting for phospho-ERK1/2, phospho-p38 MAPK, and phospho-JNK. (b) The graph represents the relative levels of phosphorylation of MAPKs. (c) 3T3-L1 cells were treated with SSE and/or ERK inhibitor PD98059. Cell lysates were prepared and subjected to immunoblotting for phospho-ERK1/2.