LEP and obesity due to melanocortin 4 receptor deficiency: Compared to lean controls, mRNA levels of GPSM1 in both epididymal WAT (eWAT) and subcutaneous WAT (scWAT) were significantly higher in mice with high-fat diet (HFD)-induced obesity (DIO) or genetic obesity caused by leptin (Ob/Ob) or leptin receptor (Db/Db) deficiency (Fig. 1a).