Institut National de la Recherche Agronomique, ADNC, Saint-Gilles, France.
J Neuroendocrinol. 2012 Aug;24(8):1096-105. doi: 10.1111/j.1365-2826.2012.02326.x.
Peripheral and central glucose sensing play a major role in the regulation of food intake. Peripheral sensing occurs at duodenal and portal levels, although the importance of these sensing sites is still controversial. The present study aimed to compare the respective influence of these sensing pathways on the eating patterns; plasma concentrations of glucose, insulin and glucagon-like peptide-1 (GLP-1); and brain activity in juvenile pigs. In Experiment 1, we characterised the changes in the microstructure as a result of a 30-min meal in eight conscious animals after duodenal or portal glucose infusion in comparison with saline infusion. In Experiment 2, glucose, insulin and GLP-1 plasma concentrations were measured during 2 h after duodenal or portal glucose infusions in four anaesthetised animals. In Experiment 3, single photon emission computed tomography brain imaging was performed in five anaesthetised animals receiving duodenal or portal glucose or saline infusions. Both duodenal and portal glucose decreased the amount of food consumed, as well as the ingestion speed, although this effect appeared earlier with the portal infusion. Significant differences of glucose and GLP-1 plasma concentrations between treatments were found at the moment of brain imaging. Both duodenal and portal glucose infusions activated the dorsolateral prefrontal cortex and primary somatosensory cortex. Only duodenal glucose infusion was able to induce activation of the prepyriform area, orbitofrontal cortex, caudate and putamen, as well as deactivation of the anterior prefrontal cortex and anterior entorhinal cortex, whereas only portal glucose infusion induced a significant activation of the insular cortex. We demonstrated that duodenal and portal glucose infusions led to the modulation of brain areas that are known to regulate eating behaviour, which probably explains the decrease of food intake after both stimulations. These stimulation pathways induced specific systemic and central responses, suggesting that different brain processing matrices are involved.
外周和中枢葡萄糖感应在调节食物摄入方面发挥着重要作用。外周感应发生在十二指肠和门静脉水平，尽管这些感应部位的重要性仍存在争议。本研究旨在比较这些感应途径对进食模式的各自影响；血浆葡萄糖、胰岛素和胰高血糖素样肽-1（GLP-1）浓度；以及幼年猪的大脑活动。在实验 1 中，我们在 8 只清醒动物中比较了十二指肠或门静脉葡萄糖输注与生理盐水输注后 30 分钟餐食引起的微观结构变化。在实验 2 中，在 4 只麻醉动物中测量了十二指肠或门静脉葡萄糖输注后 2 小时的葡萄糖、胰岛素和 GLP-1 血浆浓度。在实验 3 中，在 5 只接受十二指肠或门静脉葡萄糖或生理盐水输注的麻醉动物中进行了单光子发射计算机断层扫描脑成像。十二指肠和门静脉葡萄糖均减少了食物摄入量和摄食速度，尽管门静脉输注的这种作用出现得更早。在进行脑成像时，发现处理之间的葡萄糖和 GLP-1 血浆浓度存在显著差异。十二指肠和门静脉葡萄糖输注均激活了背外侧前额叶皮层和初级体感皮层。只有十二指肠葡萄糖输注能够诱导前梨状区、眶额皮层、尾状核和壳核以及前前额叶皮层和前内嗅皮层的去激活，而只有门静脉葡萄糖输注能够诱导岛叶皮层的显著激活。我们证明，十二指肠和门静脉葡萄糖输注导致了已知调节进食行为的大脑区域的调制，这可能解释了两种刺激后食物摄入量的减少。这些刺激途径引起了特定的全身和中枢反应，表明涉及不同的大脑处理矩阵。
