ABSORPTION, TURNOVER, & BIOCHEMICAL STUDIES OF ZN IN MAN

锌对人体健康至关重要。 锌的边际缺乏似乎 广泛存在，但其诊断标准尚未 开发 锌的吸收部位和体内平衡控制机制 锌缺乏和锌充足时胃肠道水平 在人类受试者中没有很好的表征。 具体目标是 项目是确定锌的稳态控制机制，并确定 人类受试者的边缘锌缺乏。 这些目标将 通过实验诱导一种边缘特异性缺陷来完成， 锌在成年志愿者，其次是适当的充实阶段。 的 测量参数为：锌吸收和血浆外观 用稳定同位素和中子活化新方法的动力学 分析;锌平衡，血浆中的锌浓度，红细胞， 中性粒细胞、淋巴细胞、毛发、汗液和唾液.选择性锌的测定 血浆、红细胞和中性粒细胞中的依赖性酶，深色 适应，血清维生素A和视黄醇结合蛋白;血清脂肪酸， 胆固醇、高密度脂蛋白、低密度脂蛋白和淋巴细胞功能测试。 半纯净的饮食 基于组织化大豆蛋白，将使用不同水平的锌 为了我们的研究。 所有其他宏量和微量营养素将被提供 根据RDA。 在整个实验过程中， 除了锌（在锌限制或耗竭阶段为5 mg/天， mg/天）。 锌耗尽阶段将随之而来 建议中所述的适当稳定期。 碱性 磷酸酶，血浆中的磷酸化酶和腺苷脱氨酶， 红细胞、中性粒细胞中的碱性磷酸酶（定量），以及 淋巴细胞中的核苷磷酸化酶和腺苷脱氨酶， 确定和相关的锌水平的变化，由于饮食 操纵 淋巴细胞功能活性的体外评估将 也可以做。 在消耗-充满阶段的进展过程中， 锌，胃肠道吸收的适当测量，锌 平衡，内源性分泌和血浆外观动力学稳定 将进行锌的同位素分析。 这些研究将为我们提供 用敏感的标准来诊断边缘性锌缺乏 并将提供锌的稳态控制机制， 胃肠水平。

Zinc is essential for human health. Marginal deficiency of zinc appears to be widespread but the diagnostic criteria for this have not been developed. Sites of zinc absorption and homeostatic control mechanisms at the gastro-intestinal tract level during zinc deficiency and sufficiency are not well characterized in human subjects. The specific aims of this project are to determine homeostatic control mechanisms of zinc and define marginal zinc deficiency in human subjects. These objectives will be accomplished by experimentally inducing a marginal specific deficiency of zinc in adult volunteers followed by appropriate repletion phases. The parameters of measurement will be: zinc absorption and plasma appearance kinetics using the novel method of stable isotopes and neutron activation analysis; zinc balance, zinc concentration in plasma, red cells, neutrophils, lymphocytes, hair, sweat, and saliva; assay of selected zinc dependent enzymes in the plasma, red cells, and neutrophils, dark adaptation, serum vitamin A and retinol binding protein; serum fatty acids, cholesterol, HDL, LDL, and lymphocyte function tests. A semi-purified diet based on texturized soy protein with different levels of zinc will be used for our study. All other macro and micro-nutrients will be supplied according to RDA. Throughout the experiment, the diet will remain constant except for zinc (5 mg/day during zinc restricted or depletion phase and 30 mg/day during zinc repletion phase). Zinc depletion phase will follow appropriate stabilization period as outlined in the proposal. Alkaline phosphatase, in the plasma, phosphorylase and adenosien deaminase in the red cells, alkaline phosphatase in the neutrophils (quantitative), and nucleoside phosphorylase and adenosine deaminase in the lymphocytes, will be determined and correlated with changes in zinc levels due to dietary manipulation. In vitro assessments of lymphocyte functional activity will also be made. During the progression of depletion-repletion phases for zinc, appropriate measurements of gastro-intestinal absorption, zinc balance, endogenous secretion and plasma appearance kinetics of stable isotopes of zinc will be carried out. Thus, these studies will provide us with sensitive criteria for making a diagnosis of marginal zinc deficiency and will provide homeostatic control mechanism of zinc at the gatro-intestinal level.