Mechanisms Underlying the Metabolic Pathway of Selenium and the Interactions between Selenium and Other Elements

本文采用形态分析技术研究了微量元素硒在体内的代谢转化机制.方法：1.将富集稳定同位素标记的硒化合物给予大鼠，采用HPLC-ICP-MS多元素同时检测法测定标记硒的化学形态。有机和无机形式的硒都可以用作硒的营养源。用HPLC-ICP MS法测定了无机硒、亚硒酸盐和标记富硒的硒酸盐在大鼠血液、肝脏和尿液中的化学形态。尿硒代谢产物主要来源于补硒（0.2 μg/g日粮）和补硒（2.0 μg/g日粮）。通过质谱和核磁共振氢谱数据推测其化学结构为一种新的含硒糖（硒糖）.代谢 ...更多信息 使用代表性的硒代氨基酸硒代蛋氨酸研究了有机形式硒的途径。^<82>富硒硒代蛋氨酸是化学合成的，并被注射到大鼠体内。硒代蛋氨酸中的硒以与无机亚硒酸盐相同的硒糖形式排出到尿中，表明硒代蛋氨酸中的硒即使在过量的情况下也会被硒代蛋氨酸识别为硒而代谢.通过饲喂高剂量和高剂量的无机亚硒酸盐和有机硒代蛋氨酸，比较了它们对硒的利用效率。在饲养30天后，测定了大部分器官和体液中富集硒与自然硒的相对比值。指出了硒在各器官间和两种硒营养物质之间的交换比例的特点.硒与其他元素的生物学相互作用主要集中在汞、硒与血浆蛋白硒蛋白P形成三元络合物，而砷则是主要的生物学相互作用。通过研究砷在大鼠胆汁中的形态变化，揭示了砷在肝脏中的代谢途径，特别是通过分析胆汁中砷的化学形态，即通过甲基化和还原反应以及与谷胱甘肽结合的代谢产物，揭示了砷在肝脏中的代谢途径。少

Mechanisms underlying the metabolic transformation of the micronutrient selenium in the body have been studied based on the speciation technique.1. Selenium chemicals labeled with an enriched stable isotope were administered to rats, and the chemical forms of the labeled selenium were determined by the HPLC-ICP MS method with simultaneous detection of multi-elements.2. Both organic and inorganic forms of selenium can be utilized as the nutritional source for selenium. Inorganic forms of selenium, selenite and selenate labeled with an enriched selenium were administered intravenously or orally to rats, and the chemical forms of labeled selenium in the bloodstream, liver and urine were determined by the HPLC-ICP MS method. The major urinary selenium metabolite was obtained by feeding adequate (0.2 μg/g diet) and excessive selenium (2.0 μg/g diet). The chemical structure was deduced to be a new selenium-containing sugar (selenosugar) by mass spectrometric and ^1H-NMR data.3. The metabolic … More pathways for organic forms of selenium were studied using a representative selenoamino acid, selenomethionine. ^<82>Se-Enriched selenomethionine was synthesized chemically, and it was administered to rats. Selenium of selenomethionine was excreted into the urine in the form of the same selenosugar as that of inorganic selenite, suggesting selenium of selenomethionine is metabolized with recognition of selenomethionine as selenium even by feeding it at an excessive dose.4. Efficiency for the utilization of selenium was compared between inorganic selenite and organic selenomethionine by feeding enriched ones at adequate and excessive doses. The relative ratios between enriched and naturally occurring selenium were determined for most of organs and body fluids with time after feeding them for 30 days. Characteristics in the exchange ratios were pointed out among organs and between the two nutritional selenium chemicals.5. Biological interactions of selenium with other elements were focused on the formation of ternary complex between mercury, selenium and the plasma protein selenoprotein P previuously and now on arsenic. Precise metabolic pathway for arsenic in the liver was revealed based on the speciation data after administering arsenite to rats, especially by characterizing chemical forms of arsenic in the bile, namely metabolites by methylation and reduction reactions, and conjugation with glutathione. Less