Leptin secreted by adipose tissue has a role in regulating diet and energy metabolism, and exogenous administration of leptin modulates the activity of water channel proteins thereby ameliorating nonalcoholic fatty liver disease (NAFLD) in mice, while leptin restores the coordinated action of Aquaporin-9(AQP9), thereby preventing excessive lipid accumulation in the liver in WAT and obesity (13) (Figure 4). Here, AQP9 is linked to obesity due to melanocortin 4 receptor deficiency.