FFAR1 and fatty liver disease: To further explore the mechanism of GPR40 in the regulation of LXR-induced hepatic lipogenesis, we developed an in vitro model of hepatic steatosis by exposing HepG2 cells to 5 μM of T0901317, a synthetic agonist for LXR, and then challenged this model by stimulating HepG2 cells with either 50 or 100 μM of GW9508 for 1 h prior to T0901317 treatment.