The results of this study suggested that AMK inhibited lipid accumulation by the down-regulation of the major transcription factors of the adipogensis pathway including PPAR-γ and C/EBP-α through regulation of Akt pathway and ERK 1/2 pathway in 3T3-L1 adipocytes and HFD-induced obesity mice, and AA may be main act in inhibitory effects of AMK during adipocyte differentiation. The gene discussed is CEBPA; the disease is obesity due to melanocortin 4 receptor deficiency.