Human adipo-stromal cells were incubated in culture medium containing basic fibroblast growth factor (bFGF) or in a cell-culture dish coated with bFGF. The effect of the two existence modes of bFGF on cell attachment and differentiation was evaluated. The morphology and number of cells were similar for both the bFGF modes. However, the extracellular signal-regulated kinase 1 and 2 (ERK1/2) activation of cells incubated with bFGF in the medium was stronger and lasted for a longer time period than that of bFGF in the coated form. When adipo-stromal cells were incubated in an adipogenic differentiation medium, irrespective of the mode of bFGF added, the mRNA expression of peroxisome proliferator-activated receptor gamma 2 (PPRA gamma 2) and fatty acid binding protein 2 (aP2), the glycerol-3-phosphate dehydrogenase (GPDH) activity and the cell accumulation of oil lipids were all suppressed. bFGF in the solution form inhibited the PPAR gamma 2 expression to a high extent compared with that in the coated form. It is possible that bFGF-induced ERK1/2 activation consequently inhibited the adipogenic differentiation of adipo-stromal cells. (C) Koninklijke Brill NV, Leiden, 2009