Rapid absorption of luminal polyamines in a rat small intestine ex vivo model
Rapid absorption of luminal polyamines in a rat small intestine ex vivo model
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DOI：
10.1046/j.1440-1746.2003.03020.x
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发表时间：
2003-05-01
影响因子：
4.1
通讯作者：
Bamba, T
中科院分区：
文献类型：
--
作者：
Uda, K;Tsujikawa, T;Bamba, T
背景和目的：多胺的重要来源不仅是生物合成，还包括从肠腔摄取。然而，目前还没有关于多胺在小肠中动态转运的信息。我们使用大鼠体外模型评估小肠对多胺的摄取。将离体肠置于温生理盐水浴中，经肠系膜上动脉非循环灌流。将放射性标记的腐胺、亚精胺或精胺(7.4×10(4)Bq)和1.0mLpH为7.4的磷酸盐缓冲液注入空肠腔内1min。采集门静脉血样，测定样品放射性。结果：门静脉内注入~(14)C-多胺后，门静脉内放射性即刻升高，然后逐渐降低。三种多胺的吸收模式没有不同。在注射~(14)C-多胺后的最初10分钟内，三种多胺的门静脉放射性恢复率约为61-76%，彼此间无差异。抑制腐胺降解的氨基胍显著抑制初始腐胺摄取和回收率。肠腔内注射精胺后，肠粘液中精胺抗体的免疫反应性增强。结论：在大鼠体外模型中，肠腔内多胺能迅速被肠粘膜吸收，然后转移到门静脉。预先给药显著抑制最初腐胺进入门静脉的转运。(C)2003年Blackwell出版亚洲私人有限公司。
Background and Aim: Not only biosynthesis, but also uptake from the intestinal lumen, are important polyamine sources. However, there has been no information regarding dynamic polyamine transport in the small intestine. We evaluated polyamine uptake from the small intestine using a rat ex vivo model.Methods: The organ block consisting of the small intestine and blood vessels was used. The isolated small intestine was placed in a warmed saline bath and perfused in a non-circulating manner via the superior mesenteric artery. Radio-labeled putrescine, spermidine or spermine (7.4 x 10(4) Bq), with 1.0 mL of phosphate buffer saline (pH 7.4) was instilled into the jejunal lumen for 1 min. Blood samples from the portal vein were collected and sample radioactivity was determined. In another experiment, an immunohistochemical study of polyamine was performed.Results: After (14) C-polyamine instillation, radioactivity in the portal vein samples immediately increased and then decreased gradually. The absorptive pattern did not differ among the three polyamines. The recovery rates from radioactivity at the portal vein among the three polyamines were approximately 61-76% during the initial 10 min after the administration of (14) C-polyamine, and were not different from each other. Aminoguanidine, which inhibits putrescine degradation, significantly suppressed initial putrescine uptake and recovery percentage. The intraluminal administration of spermine caused an increase in the immunoreactivity of the spermine antibody in the intestinal villi.Conclusion: Luminal polyamines were rapidly absorbed by the intestinal mucosa and then subsequently transferred into the portal vein using a rat ex vivo model. The prior administration of aminoguanidine significantly inhibited initial putrescine transport into the portal vein. (C) 2003 Blackwell Publishing Asia Pty Ltd.