Wakonig P, Költringer P, Lind P, Eber O, Wawschinek O
Internen Abteilung, Krankenhauses der Barmherzigen, Brüder Graz- Eggenberg.
Acta Med Austriaca. 1988;15(1):15-9.
More than 99% of circulating thyroid hormones are bound with defined capacity and affinity to transport proteins such as thyroxine binding globulin, albumin and prealbumin. Variants of albumin and/or prealbumin, often familial, will bind T4 and sometimes T3 with increased affinity causing higher TT4 and TT3 values respectively. In determining fT4 and fT3 by analogue tracer its binding to protein variants will also lead to falsely raised free parameters. Thus the possibility of a false diagnosis of hyperthyroidism arises. Also the presence of T4 and T3 autoantibodies will cause misleading findings of increased thyroid hormone parameters as against euthyroid metabolism. For determining the pattern of T4 and T3 protein binding as well as autoantibodies radioactive labelled T4 or T3 is incubated with the patients serum. Transport proteins are separated by means of horizontal agarose gel electrophoresis with water cooling. The gel is sectioned and the activity of individual gel particles is measured in a Gammacounter. The activity graph shows with high precision the binding pattern of T4 and T3 to transport proteins. Moreover, this method also serves to determine any possible T4 and T3 autoantibodies, indicated by a peak in the activity graph in the gamma globulin range.
超过99%的循环甲状腺激素以一定的容量和亲和力与甲状腺素结合球蛋白、白蛋白和前白蛋白等转运蛋白结合。白蛋白和/或前白蛋白的变体，通常是家族性的，会以更高的亲和力结合T4，有时也会结合T3，分别导致TT4和TT3值升高。在用类似物示踪剂测定游离T4和游离T3时，其与蛋白质变体的结合也会导致游离参数被错误地升高。因此，有可能会误诊为甲状腺功能亢进。此外，T4和T3自身抗体的存在也会导致甲状腺激素参数升高的误导性结果，而实际上代谢处于甲状腺功能正常状态。为了确定T4和T3与蛋白质的结合模式以及自身抗体，将放射性标记的T4或T3与患者血清一起孵育。通过带水冷装置的水平琼脂糖凝胶电泳分离转运蛋白。将凝胶切片，并在γ计数器中测量各个凝胶颗粒的活性。活性图谱能高精度地显示T4和T3与转运蛋白的结合模式。此外，该方法还可用于确定任何可能存在的T4和T3自身抗体，γ球蛋白范围内活性图谱上的一个峰值即表明存在自身抗体。
