Nampt (Visfatin/PBEF) (rat) (rec.)

Nicotinamide phosphoribosyltransferase (Nampt; pre-B cell colony-enhancing factor; PBEF; Visfatin) is an 52kDa adipokine secreted by adipose tissue and involved in the biosynthesis of nicotinamide adenine dinucleotide (NAD+). Two forms of Nampt exist, an intracellular form (iNampt) and an extracellular form (eNampt). While the function of iNampt as an essential and rate-limiting NAD+ biosynthetic enzyme is well established, the physiological role of eNampt is still a matter of debate. Nampt has various functions, including the promotion of vascular smooth muscle cell maturation and inhibition of neutrophil apoptosis. It activates insulin receptor and has insulin-mimetic effects, lowering blood glucose and improving insulin sensitivity. The protein is highly expressed in visceral fat and serum levels of the protein correlate with obesity. Recently NAMPT extracellular (eNAMPT) has been shown to be secreted from macrophages in muscles and to triggers a proliferative signal of muscle stem cell (MusC) by binding to CCR5 located at the surface receptor of MusC.