Mechanism of induction of mucosal ornithine decarboxylase by food.
Mechanism of induction of mucosal ornithine decarboxylase by food.
复制标题
食物诱导粘膜鸟氨酸脱羧酶的机制。
DOI：
10.1152/ajpgi.1986.251.3.g370
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Johnson,LR
中科院分区：
文献类型：
--
作者：
Tabata,K;Johnson,LR
重新喂养禁食的大鼠会显着增加小肠和结肠粘膜中的鸟氨酸脱羧酶（ODC）活性。然而，尚未确定负责该激活的试剂和导致激活的途径。目前的工作研究了 ODC 活性的刺激是通过体液介导还是直接介导，以及膳食胺是否可能在一定程度上负责激活。雄性 Sprague-Dawley 大鼠在手术准备 Thiry-Vella 空肠环 1 周后使用。大鼠禁食 48 小时后重新喂食 2 小时后，完整空肠粘膜中的 ODC 活性增加了 40 倍，旁路节段粘膜中的 ODC 活性增加了 4 倍。将肠道内容物（从额外喂食的大鼠获得）注射到绕过的环路中，导致 2 小时后测量的环路中 ODC 活性增加 10 倍。注射冻干肠道内容物以去除膳食胺，酶活性没有变化。在冻干肠道内容物中添加 400 mol 二甲胺，酶活性恢复到之前水平的 80%。这些数据得出以下结论：进餐后，粘膜 ODC 通过体液和直接机制激活，饮食成分的直接刺激似乎是所涉及的主要机制，并且饮食胺可能是参与直接增加酶活性的试剂之一。
Refeeding fasted rats dramatically increases ornithine decarboxylase (ODC) activity in the mucosa of the small intestine and colon. The agents responsible for that activation and pathways leading to activation, however, have not been identified. The current work examines whether stimulation of ODC activity is mediated humorally or directly and whether dietary amines might be in part responsible for activation. Male Sprague-Dawley rats were used 1 wk after they were surgically prepared with Thiry-Vella jejunal loops. Two hours after refeeding rats fasted for 48 h, ODC activity increased 40-fold in mucosa from the intact jejunum and 4-fold in the mucosa of the bypassed segments. The injection of intestinal contents (obtained from additional fed rats) into the bypassed loop caused a 10-fold increase in ODC activity in the loop measured 2 h later. Injection of gut contents, lyophilized to remove dietary amines, produced no change in enzyme activity. The addition of 400 mol dimethylamine to lyophilized gut contents restored enzyme activation to 80% of the previous level. These data allow the following conclusions: following a meal mucosal ODC is activated by both humoral and direct mechanisms, direct stimulation by dietary constituents appears to be the predominant mechanism involved, and dietary amines may be one of the agents involved in directly increasing enzyme activity.