Parenteral nutrition selectively decreases protein synthesis in the small intestine
Parenteral nutrition selectively decreases protein synthesis in the small intestine
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DOI：
10.1152/ajpgi.1998.274.1.g131
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发表时间：
1998-01-01
影响因子：
4.5
通讯作者：
Reeds, PJ
中科院分区：
文献类型：
--
作者：
Dudley, MA;Wykes, LJ;Reeds, PJ
我们研究了胃肠外或肠内喂养的元素饮食对总粘膜蛋白和乳糖酶根皮苷水解酶（LPH）合成的影响。将导管放置在12只3日龄猪的胃、颈静脉和颈动脉中。一半的动物肠内给予基本方案，另一半胃肠外给予。6天后，动物静脉输注[H-2（3）]亮氨酸6 h并处死，收集每只动物的空肠中段进行分析。肠外饲喂和肠内饲喂仔猪的空肠中段重量分别为8 +/- 1.5和17 +/- 1.6 g。LPH活性（μ mol.min（-1）.g蛋白质（-1））在胃肠外饲喂仔猪中显著高于肠内饲喂仔猪。胃肠外喂养动物的总小肠LPH活性低于肠内喂养动物。LPH mRNA相对于延伸因子-1 α mRNA的丰度在组间没有差异。胃肠外喂养动物的总粘膜蛋白和LPH合成率（分别为67 +/- 7和66 +/- 7%/天）显著低于肠内喂养动物（分别为96 +/- 7和90 +/- 6%/天）。总粘膜蛋白的绝对合成率（每克粘膜合成的蛋白量）在胃肠外喂养的仔猪中显著低于肠内喂养的仔猪。然而，LPH的绝对合成速率不受营养素给药途径的影响。这些结果表明，小肠通过维持LPH的绝对合成速率在与肠内喂养动物相同的水平，部分补偿了胃肠外喂养的影响。
We investigated the effects of an elemental diet fed parenterally or enterally on total mucosal protein and lactase phlorizin hydrolase (LPH) synthesis. Catheters were placed in the stomach, jugular vein, and carotid artery of 12 3-day-old pigs. Half of the animals were given an elemental regimen enterally and the other half parenterally. Six days later, animals were infused intravenously with [H-2(3)]leucine for 6 h and killed, and the midjejunum of each animal was collected for analysis. The weight of the midjejunum was 8 +/- 1.5 and 17 +/- 1.6 g in parenterally fed and enterally fed piglets, respectively. LPH activities (mu mol.min(-1).g protein(-1)) were significantly higher in parenterally vs. enterally fed piglets. Total small intestinal LPH activities were lower in parenterally vs. enterally fed animals. The abundance of LPH mRNA relative to elongation factor-1 alpha mRNA was not different between groups. The fractional synthesis rate of total mucosal protein and LPH was significantly lower in parenterally fed animals (67 +/- 7 and 66 +/- 7%/day, respectively) than in enterally fed animals (96 +/- 7 and 90 +/- 6%/day, respectively). The absolute synthesis rate (the amount of protein synthesized per gram of mucosa) of total mucosal protein was significantly lower in parenterally fed than in enterally fed piglets. However, the absolute synthesis rate of LPH was unaffected by the route of nutrient administration. These results suggest that the small intestine partially compensates for the effects of parenteral feeding by maintaining the absolute synthesis rate of LPH at the same levels as in enterally fed animals.