...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Inorganic Biochemistry: An Interdisciplinary Journal >Dietary minerals in the gastrointestinal tract: hydroxypolymerisation of aluminium is regulated by luminal mucins
【24h】

Dietary minerals in the gastrointestinal tract: hydroxypolymerisation of aluminium is regulated by luminal mucins

机译：胃肠道中的饮食矿物质：铝的羟基聚合受腔粘蛋白调节

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The regulation of mineral absorption in the gastrointestinal tract is poorly understood. Recent work has identified an intracellular metal-ion transporter but considerable evidence suggests that both soluble and mucosally associated luminal metal-binding ligands regulate initial uptake. Molecules ranging from low molecular weight organic acids to large glycoproteins have been suggested but a definite role for any such species has remained elusive. Here, a series of analytical techniques. allowing for this wide variation in potential binding ligands, was applied to the study of intestinal contents and tissue of rats following different feeding protocols. Aluminum, that has a low endogenous background and maintains a high concentration in the gastrointestinal tract, was investigated as a suitable dietary metal with hydrolytic behaviour similar, for example, to copper, iron and zinc. High resolution nuclear magnetic resonance spectroscopy identified a number of endogenous low molecular weight weak ligands that are secreted into the intestinal lumen. These may slow the rate of hydroxy-polymerisation of hydrolytic metals, allowing their effective donation to less mobile,higher molecular weight binding ligands. Histochemical staining suggested that such species may be soluble mucins as these were consistently associated with luminal aluminium. Significantly, this interaction prevented hydroxy/phosphate precipitation of aluminium, even at supraphysiological levels of the element. This was confirmed with X-ray micro-analysis investigations of ex vivo luminal contents. Nevertheless, from phase distribution experiments, the majority (60-95%) of luminal aluminium was associated with the intestinal solid phase and further histochemistry confirmed this to be gelatinous mucus, chiefly as the mucosally adherent layer. All results suggest a major role for mucus in regulating the gastrointestinal absorption of aluminium. It is proposed that, initially, soluble luminal mucus prevents the hydroxy-precipitation of hydrolytic metals at intestinal pH, allowing their effective donation to the mucus layer. Based on the differing reported metal-mucus interactions, elements that bind well to mucus (Al~(3+), Fe~(3+)), with kinetically slow rates of ligand exchange (Al~(3+)
机译：对胃肠道中矿物质吸收的调节了解甚少。最近的工作已经确定了一种细胞内金属离子转运蛋白，但大量证据表明可溶性和与黏膜相关的腔内金属结合配体均调节初始摄取。已经提出了从低分子量有机酸到大糖蛋白的分子，但是对于任何这样的物种，确定的作用仍然难以捉摸。这里介绍了一系列分析技术。考虑到潜在的结合配体的这种广泛变化，将其用于研究遵循不同喂养方案的大鼠的肠内容物和组织。具有低内源性背景并且在胃肠道中保持高浓度的铝被研究为具有类似于铜，铁和锌的水解行为的合适饮食金属。高分辨率核磁共振波谱鉴定了许多内源性低分子量弱配体，这些配体被分泌到肠腔中。这些可能减慢水解金属的羟基聚合速度，从而允许它们有效地捐赠给流动性较低，分子量较高的配体。组织化学染色表明，此类物质可能是可溶性粘蛋白，因为它们与腔铝一直相关。显着地，这种相互作用即使在元素的超生理水平上也阻止了铝的羟基/磷酸盐沉淀。通过离体腔内容物的X射线微分析研究证实了这一点。然而，从相分布实验来看，大部分（60-95％）的腔铝与肠道固相有关，进一步的组织化学证实这是凝胶状粘液，主要是粘膜粘附层。所有结果表明，粘液在调节铝的胃肠道吸收中起主要作用。有人提出，最初，可溶的腔内粘液可防止在肠道pH值下水解金属的羟基沉淀，从而将其有效地捐赠给粘液层。根据报道的不同的金属-粘液相互作用，元素与粘液良好结合（Al〜（3 +），Fe〜（3+）），而配体交换的动力学速率较慢（Al〜（3 +）

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号