Intestinal mucosa in diabetes: synthesis of total proteins and sucrase-isomaltase.
Intestinal mucosa in diabetes: synthesis of total proteins and sucrase-isomaltase.
复制标题
糖尿病的肠粘膜：总蛋白和蔗糖酶-异麦芽糖酶的合成。
DOI：
10.1152/ajpgi.1986.250.6.g788
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Malinowski,RL
中科院分区：
文献类型：
--
作者：
Olsen,WA;Perchellet,E;Malinowski,RL
胰岛素缺乏对肌肉和肝脏氮代谢的影响已得到广泛研究，最近在体内证实链脲佐菌素诱导的糖尿病大鼠蛋白质合成受损。尽管小肠粘膜对整体蛋白质代谢有重要贡献，但胰岛素缺乏对肠道蛋白质合成的影响尚未完全确定。我们研究了链脲佐菌素诱导的糖尿病对小肠粘膜总蛋白合成的影响，以及对肠上皮细胞刷状缘膜蔗糖酶-异麦芽糖酶的单酶蛋白合成的影响。我们使用McNurlan、Tomkins和Garlick（Biochem.J.178：373-379，1979）的超剂量技术，以尽量减少测量前体苯丙氨酸比放射性的困难，并在注射标记氨基酸后20分钟测定掺入粘膜蛋白和蔗糖酶-异麦芽糖酶的情况。糖尿病并没有改变粘膜质量所确定的重量和含量的蛋白质和DNA在5天后注射链脲佐菌素。蔗糖酶-异麦芽糖酶合成速率的增加在第3天开始发展，而总蛋白的增加在第5天发展。因此，肠粘膜蛋白质合成不是胰岛素敏感的过程。
The effects of insulin deficiency on nitrogen metabolism in muscle and liver have been extensively studied with recent in vivo demonstration of impaired protein synthesis in rats with streptozotocin-induced diabetes. Despite the significant contribution of small intestinal mucosa to overall protein metabolism, the effects of insulin deficiency on intestinal protein synthesis have not been completely defined. We studied the effects of streptozotocin-induced diabetes on total protein synthesis by small intestinal mucosa and on synthesis of a single enzyme protein of the enterocyte brush-border membrane sucrase-isomaltase. We used the flooding-dose technique of McNurlan, Tomkins, and Garlick (Biochem. J. 178: 373–379, 1979) to minimize the difficulties of measuring specific radioactivity of precursor phenylalanine and determined incorporation into mucosal proteins and sucrase-isomaltase 20 min after injection of the labeled amino acid. Diabetes did not alter mucosal mass as determined by weight and content of protein and DNA during the 5 days after injection of streptozotocin. Increased rates of sucrase-isomaltase synthesis developed beginning on day 3, and those of total protein developed on day 5. Thus intestinal mucosal protein synthesis is not an insulin-sensitive process.