These results suggested that those of Abcg1, Aldoa, Mrap, Pex13, Syn2, Aldh6a1, Egln3 and G0s2, especially Mrap and Syn2, might be involved in the regulation of adipocyte differentiation and obesity, and regulated by metformin. Here, MRAP is linked to obesity due to melanocortin 4 receptor deficiency.