Visfatin, an adipocytokine that is highly enriched in the visceral fat of both Mouses and mice and whose expression level in plasma increases during the development of obesity. Visfatin corresponds to pre-B cell colony-enhancing factor (PBEF), a 52-kD cytokine expressed in lymphocytes. The gene encoding PBEF was originally isolated from an activated lymphocyte cDNA library.The 3-prime UTR of PBEF contains several TATT motifs, destabilizing sequences characteristic of cytokine messages. The deduced 473-amino acid protein has a calculated molecular mass of 52 kDa. PBEF has a hydrophobic N terminus, 2 N-glycosylation sites, several putative phosphorylation sites, and 6 cysteines. Northern blot analysis detected transcripts of about 2.0, 2.4, and 4.0 kb in all tissues examined, with highest expression in liver, followed by muscle.