Burk Raymond F, Hill Kristina E
Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0252; email:
Annu Rev Nutr. 2015;35:109-34. doi: 10.1146/annurev-nutr-071714-034250. Epub 2015 May 13.
Selenium is regulated in the body to maintain vital selenoproteins and to avoid toxicity. When selenium is limiting, cells utilize it to synthesize the selenoproteins most important to them, creating a selenoprotein hierarchy in the cell. The liver is the central organ for selenium regulation and produces excretory selenium forms to regulate whole-body selenium. It responds to selenium deficiency by curtailing excretion and secreting selenoprotein P (Sepp1) into the plasma at the expense of its intracellular selenoproteins. Plasma Sepp1 is distributed to tissues in relation to their expression of the Sepp1 receptor apolipoprotein E receptor-2, creating a tissue selenium hierarchy. N-terminal Sepp1 forms are taken up in the renal proximal tubule by another receptor, megalin. Thus, the regulated whole-body pool of selenium is shifted to needy cells and then to vital selenoproteins in them to supply selenium where it is needed, creating a whole-body selenoprotein hierarchy.
体内的硒受到调节，以维持重要的硒蛋白并避免毒性。当硒有限时，细胞利用它来合成对它们最重要的硒蛋白，从而在细胞内形成硒蛋白等级体系。肝脏是硒调节的中心器官，它产生排泄性硒形式以调节全身的硒。它通过减少排泄并以细胞内硒蛋白为代价将硒蛋白P（Sepp1）分泌到血浆中来应对硒缺乏。血浆Sepp1根据组织中Sepp1受体载脂蛋白E受体-2的表达情况分布到各组织，从而形成组织硒等级体系。N端Sepp1形式被另一种受体巨蛋白摄取到肾近端小管中。因此，受调节的全身硒库转移到有需求的细胞，然后再到细胞内的重要硒蛋白，以便在需要的地方提供硒，从而形成全身硒蛋白等级体系。
