This study investigated the effect of prostaglandin E2 derivative, enprostil, on the hepatic lipid metabolism of Japanese quail. In experiment 1, the birds received 0.1, 1, 10 or 100 micrograms enprostil/kg body weight intraperitoneally, and they were killed after 10, 30, 60 and 120 min. After 60 min, hepatic triacylglycerol content was reduced most effectively by 10 micrograms enprostil/kg body weight. In experiment 2, effect of enprostil (10 micrograms/kg body weight) on liver enzyme activities associated with lipid metabolism and plasma lipid concentrations was examined. There were no significant differences in malic enzyme and carnitine palmitoyltransferase activities. Peroxisomal beta-oxidation in birds which received enprostil was significantly lower than that in birds receiving the vehicle. Enprostil caused a significant decrease in plasma triacylglycerol and non-esterified fatty acid concentration. We conclude that the administration of enprostil reduces hepatic triacylglycerol content through the decreased influx of non-esterified fatty acid.