ABSTRACT
Visceral fat accumulation has been shown to play crucial roles in the development of obesity-related disorders. Additionally, insulin resistance in visceral fat obesity is thought to be one of the key abnormalities related to metabolic disorders. Given these clinical fi ndings, adipocyte functions have been intensively investigated in the past 10 years, and adipocytes have been revealed to act as endocrine cells, secreting various bioactive substances termed adipokines. Current evidence suggests that these secretory products are implicated in modulation of appetite, insulin sensitivity, energy expenditure, infl ammation and immunity. One of the most recent proteins shown to be highly expressed in adipose tissue is visfatin, originally identifi ed as pre-B-cell colony-enhancing factor (PBEF). Visfatin appears to be preferentially produced by the visceral adipose tissue and has insulin-mimetic actions. Th erefore, visfatin may be involved in the development of obesity-related diseases. In addition, recent data indicate that visfatin may exert various cardiovascular eff ects and may be implicated in infl ammatory disease states beyond insulin resistance, such as acute lung injury and infl ammatory bowel disease. Some of these observed actions of visfatin indicate that this secreted protein may be an interesting therapeutic target. Several studies, however, suggest that our understanding of visfatin is still speculative.
