Postabsorptive glucose decreases excitatory effects of taste on ingestion

To test the hypothesis that postprandial rises of plasma glucose attenuate the motivation derived from positive tastes, we analyzed the effects of intraperitoneal (ip) injections of glucose on sham feeding, a preparation in which food intake is motivated primarily by taste sensations. Ip glucose suppressed sham feeding, with maximal suppressions approximately 42% but only when glucose was administered contiguous with oropharyngeal stimulation. The food intake inhibition produced by ip glucose interacted with palatability; smaller doses of glucose were required to suppress less concentrated sucrose solutions. Closing the gastric cannula increased the potency with which ip glucose inhibited eating, suggesting synergy of postabsorptive glucose with other postgastric satiety signals. The inhibition of eating produced by ip glucose did not result from malaise. Thus postabsorptive rises of plasma glucose decrease the ability of taste cues to drive ingestion and suggest that this phenomenon may contribute to spontaneous meal termination.