PPARG and obesity due to melanocortin 4 receptor deficiency: Our previous research reported that nor-NOHA, as an arginase inhibitor, significantly increased phosphorylated AMPK α, reduced the gene expression of ADRP and SCD-1 modulated by PPAR-γ2, and contributed to the development of fatty liver, suggesting the improvement of lipid metabolism in the liver and the anti-obesity effect in vivo and in vitro [14].