Luminal and systemic signals trigger intestinal adaptation in the juvenile python.
Luminal and systemic signals trigger intestinal adaptation in the juvenile python.
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腔内和全身信号触发幼年蟒蛇的肠道适应。
DOI：
10.1152/ajpgi.2000.279.6.g1177
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Diamond,J
中科院分区：
文献类型：
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作者：
Secor,SM;Whang,EE;Lane,JS;Ashley,SW;Diamond,J
幼蟒在进食后肠道质量和肠道转运蛋白活动急剧上调。因为在蟒蛇身上做手术和在实验室里维持它们也很容易，所以我们使用蟒蛇模型来检查肠道适应的信号和因子。我们手术分离了小肠的中间三分之一，使其肠系膜神经和血管供应完好无损。通过近端和远端三分之一之间的端到端吻合恢复肠的连续性。在蛇进食后的24小时内，重新吻合的近端和远端部分（接受肠道营养）的氨基酸和葡萄糖摄入量上调了15倍，肠道质量增加了一倍，因此很快就达到了与正常喂食的全长肠道相同的总营养吸收能力。然而，在这个时候，分离的中间部分，没有接受任何肠道营养，在营养吸收和形态上都没有从禁食状态改变。饲喂后3天，分离的中间节段营养摄取上调至与重新吻合的近端节段和远端节段相同的水平，但仍然没有任何明显的形态学反应。再吻合肠和分离的中间段的对比结果表明，肠道营养物质和/或胰腺胆道分泌物是触发转运蛋白和肠质量快速上调的因素，系统神经或激素信号随后触发转运蛋白调节，但没有营养反应。
Juvenile pythons undergo large rapid upregulation of intestinal mass and intestinal transporter activities upon feeding. Because it is also easy to do surgery on pythons and to maintain them in the laboratory, we used a python model to examine signals and agents for intestinal adaptation. We surgically isolated the middle third of the small intestine from enteric continuity, leaving its mesenteric nerve and vascular supply intact. Intestinal continuity was restored by an end-to-end anastomosis between the proximal and distal thirds. Within 24 h of the snake's feeding, the reanastomosed proximal and distal segments (receiving luminal nutrients) had upregulated amino acid and glucose uptakes by up to 15-fold, had doubled intestinal mass, and thereby soon achieved total nutrient uptake capacities equal to those of the normal fed full-length intestine. At this time, however, the isolated middle segment, receiving no luminal nutrients, experienced no changes from the fasted state in either nutrient uptakes or in morphology. By 3 days postfeeding, the isolated middle segment had upregulated nutrient uptakes to the same levels as the reanastomosed proximal and distal segments, but it still lacked any appreciable morphological response. These contrasting results for the reanastomosed intestine and for the isolated middle segment suggest that luminal nutrients and/or pancreatic biliary secretions are the agents triggering rapid upregulation of transporters and of intestinal mass and that systemic nerve or hormonal signals later trigger transporter regulation but no trophic response.