Fatty acid oxidation and glucose utilization interact to control food intake in rats

To determine whether glucose and fat metabolism interact to control food intake, rats were administered 2-deoxyglucose (2-DG), which inhibits glucose utilization, and methyl palmoxirate (MP), which inhibits fatty acid oxidation. Combined treatment with 2-DG and MP increased food intake in a synergistic fashion. This synergistic effect was observed even at doses of the two agents that alone did not increase food intake, and it was expressed by either an initiation of eating or a prolonged bout of eating, depending on the testing conditions. Metabolic measures of circulating substrates, liver glycogen, and gastric contents confirmed that the drugs had their intended metabolic effects and revealed no evidence that one drug enhanced the direct metabolic action of the other. The results provide direct evidence that glucose and fat metabolism exert a coordinated control over feeding behavior and suggest the existence of a common integrative mechanism in that control.