RBP4 and obesity due to melanocortin 4 receptor deficiency: A large body of literature has reported that adiponectin plays a positive role in control of obesity [40] and its overexpression enhances insulin sensitivity in part through effects on hepatic glucose production [41]–[43], whereas abnormal expression/secretion of some of adipokines, such as leptin, RBP4, and RANTES, is linked to obesity and obesity-related disease [44]–[46].