Sterol regulatory element binding proteins (SREBPs) are transcription factors that have pivotal roles in lipogenesis and fat metabolism. The activation of SREBPs requires escort to the Golgi by SREBP cleavage-activating protein (SCAP) followed by proteolytic release of SREBP from the Golgi. Fatostatin is an inhibitor of SREBP activation, preventing SCAP-mediated escort of either SREBP-1 or SREBP-2 to the Golgi (IC50 = 5.6 μM). This blocks constitutive SREBP-mediated gene expression in the human prostate cancer cell line DU145. Fatostatin prevents insulin-induced adipogenesis of 3T3-L1 cells as well as growth induced by insulin-like growth factor 1 in DU145 cells (IC50 = 0.1 μM). Through its actions on SCAP/SREBP-1, it inhibits high glucose-induced upregulation of TGF-β in primary rat mesangial cells. This compound also alters lipid metabolism in vivo, reducing hepatic fat accumulation in ob/ob mice.