Kawano R, Ikeda A, Mishima N, Harada T
J Med. 1986;17(5-6):313-30.
Iodinated proteins in normal thyroid tissue extracts were analyzed immunochemically, immunohistochemically and physicochemically after isoelectric focusing. An albumin-like protein ranging from pI 4.80 to 5.21 was found in normal human thyroid tissue extracts, and its pI range was not compatible with that of serum albumin ranging from pI 4.85 to 6.16. An immunodiffusion study suggests that T3 loosely combines with the albumin-like protein, and that this compound is so-called thyroid albumin. Amino acid analysis revealed a difference in the basic amino acid composition of thyroid albumin and serum albumin, and our immunohistochemical study showed that thyroid albumin and T3 were localized in follicular epithelial cells, but not in the colloid. Based on these results, thyroid albumin may be described as consisting of T3 and an albumin-like protein which is distinguishable from serum albumin and distinct from thyroglobulin immunochemically. It appears that a low molecular weight hormone like T3 can be detected when it combines with a protein molecule. Recently, DeGroot et al. (1975) suggested a collateral pathway of hormone metabolism through the thyroid albumin in thyroid follicular cells. Our results seem to support the existence of this pathway.
对正常甲状腺组织提取物中的碘化蛋白进行了等电聚焦后，采用免疫化学、免疫组织化学和物理化学方法进行分析。在正常人甲状腺组织提取物中发现了一种等电点范围在4.80至5.21之间的类白蛋白，其等电点范围与血清白蛋白的等电点范围（4.85至6.16）不相符。免疫扩散研究表明，T3与类白蛋白松散结合，这种化合物就是所谓的甲状腺白蛋白。氨基酸分析揭示了甲状腺白蛋白和血清白蛋白在碱性氨基酸组成上的差异，我们的免疫组织化学研究表明，甲状腺白蛋白和T3定位于滤泡上皮细胞，而不是在胶质中。基于这些结果，甲状腺白蛋白可被描述为由T3和一种类白蛋白组成，这种类白蛋白与血清白蛋白不同，在免疫化学上也与甲状腺球蛋白不同。似乎当低分子量激素如T3与蛋白质分子结合时就可以被检测到。最近，DeGroot等人（1975年）提出了一条通过甲状腺滤泡细胞中的甲状腺白蛋白的激素代谢旁支途径。我们的结果似乎支持了这条途径的存在。
