Effects of exendin-4 on lipid accumulation and mRNA expression of SREBP-1, FAS, PPAR-α, and CPT-1 mediated by AMPK activation. Exendin-4 (20 nM), compound C (10 μM), or AICAR (1 mM) were used to assess the effect of AMPK in MCs cultured with 1% BSA or 200 μM oleate-BSA. Deposition of neutral lipid was characterized by Oil Red O (a), and triglyceride (TG) contents of the cell were measured by glyceridase assay (b). The mRNA expressions of SREBP-1, FAS, PPAR-α, and CPT-1 were measured by quantitative RT-PCR (c–f). ∗P < 0.05 vs. BSA group; &P < 0.05 and &&P < 0.01 vs. OA group; #P < 0.05 and ##P < 0.01 vs. OA+EX group, n = 3.