Stromal preadipocytes from human omental adipose tissues were isolated with enzyme-digesting method,and cultured for inducing differentiation.Preadipocyte factor-1 was abundant during preadipoeyte stage,whereas lipoprotein lipase and PPARγ2 mRNA were rapidly up-regulated at early stage of differentiation and CCAAT/enhancer binding protein expression was increased rather late.In addition,resistin expression and secretion was primarily detectable in preadipocytes,leptin was gradually increased during adipogenesis,whereas adiponectin appeared specifically in mature adipocytes.Insulin-like growth factor-Ⅰ secretion was remarkably detected in both preadipocytes and mature adipocytes.