Visfatin is predominantly secreted from visceral adipose tissue both in humans and mice. This protein has also been reported to be a cytokine (pre-B cell colony-enhancing factor, PBEF) that promotes B cell maturation and inhibits neutrophil apoptosis, or a visceral-fat derived hormone that acts by binding and activating the insulin receptor. Recombinant mouse visfatin was expressed in E.coli and purified by using conventional chromatography techniques.