Postabsorptive factors are important for satiation in rats after a lipid meal

We examined satiation after intraduodenal infusion of triglyceride with or without Pluronic L-81 (L-81) in rats. L-81 suppresses lipid transport into mesenteric lymph by preventing the formation of chylomicrons. Under unrestrained conditions, a lipid emulsion was infused into 24-h fasted rats intraduodenally for 8 h. After the infusion, food intake during the first 30 min and blood samples were measured. Food intake after the 8-h lipid infusion decreased significantly (-75%) compared with that of rats infused with vehicle only, and the effect of the lipid meal was time dependent. The satiation effect of the lipid was lost as a result of L-81 treatment, but food intake was still significantly decreased (-22%). The loss of inhibition of food intake by the feeding of lipid plus L-81 was totally reversed by the cessation of L-81 infusion. In rats infused with the lipid emulsion, plasma levels of triglyceride and apolipoprotein A-IV increased significantly. This increase was abolished by the presence of L-81 in the lipid infusate. The present study indicates that postabsorptive factors are important for anorexia observed after a lipid meal in addition to preabsorptive factors. This study further supports our previous conclusion that apolipoprotein A-IV is an important postabsorptive factor for satiation after a lipid meal.