NAMPT and obesity due to melanocortin 4 receptor deficiency: Assessment of visfatin mRNA levels in adipose tissue (AT), as a result of RSG treatment in the Otsuka Long Evans Tokushima Fatty (OLETF) rat (an animal model of T2DM with obesity), revealed increased mRNA expression levels in visceral fat depots [15], although decreased visfatin mRNA expression levels were reported in 3T3-L1 adipocytes [16].