RFamide neuropeptides NPFF and NPAF affect gene expression in mature 3T3-L1 adipocytes but their role oil adipogenesis is Unknown. Here, we show that NPFF, NPAF, and NPSF inhibited the differentiation of 3T3-F442A preadipocytes in a concentration-dependent manner, but had no effect on 3T3-L1 adipogenesis. All three neuropeptides also blocked the adipose differentiation of normal and lipoma-derived human preadipocytes. The antiadipogenic effect of RFamide neuropeptides was linked with the overexpression of Id3 gene and the inhibition by NPAF remained after neuropeptide removal and further incubation of 3T3 cells with adipogenic medium. Our results show that NPFF, NPAF and NPSF negatively affect adipogenesis and suggest that these compounds participate in the regulation of the adipose tissue development by the central nervous system. (C) 2008 Elsevier Inc. All rights reserved