Evidence for a vagally mediated satiety signal derived from hepatic fatty acid oxidation

To test the possibility that vagally mediated signals derived from hepatic fatty acid oxidation affect feeding, we investigated the influence of selective hepatic vagotomy on the acute hyperphagic effect of the fatty acid oxidation inhibitor 2-mercaptoacetate (MA) in rats kept on a medium fat diet (18% fat). An i.p. injection of MA (400 mumol/kg b.wt.) stimulated feeding in sham-vagotomized rats clearly more than in vagotomized rats. A high dose of MA (800 mumol/kg b.wt.) initially increased food intake in sham-vagotomized but not in vagotomized rats and later decreased food intake similarly in both surgical groups. MA retained its potency to stimulate feeding after an i.p. injection of atropine methylnitrate (5 mg/kg b.wt.). These results indicate that hepatic fatty acid oxidation provides a satiety signal that is mediated by vagal afferents.