Feeding decreases FAAH activity and mRNA expression in rat jejunum. Effects of free feeding (FF), 24-h food deprivation (FD), and refeeding (10, 30, 60 and 120 min) on FAAH activity (A), FAAH mRNA expression (B) and FAAH protein levels (B inset). C, Effects of vehicle (FD, 0.1% DMSO), URB597 (URB, 0.1μM), THL (1μM) and CCP (5μM) on FAAH activity in intestinal mucosal layer of food-deprived rats. *p < 0.05; **p < 0.01 vs FD, n = 6. D, Representative immunostaining showing the localization of FAAH in the duodenal epithelium and lamina propria of wild-type C57/BL6 mice. E, Absence of immunoreactive FAAH in corresponding structures of FAAH−/− mice; Scale bar, 50 μm.