Sadler W A, Lynskey C P
Clin Chem. 1982 Jan;28(1):63-8.
Three erythrocyte proteins, one identified as hemoglobin, bind thyroid hormones. Using a dextran/charcoal radioimmunoassay for thyroxin in dried blood spots, we demonstrate that such binding differs with the buffer used. Barbital, phosphate, and borate buffers significantly enhance the binding more than glycine and tris(hydroxymethyl)methylamine buffers. Binding is not affected by agents commonly used to inhibit thyroxin binding to serum proteins. A highly significant nonlinear direct relationship between sample storage (temperature and duration) and increased thyroxin-erythrocyte binding is documented, together with an associated decrease in assayed concentrations of thyroxin. However, concomitant serial measurement of thyroxin with polyethylene glycol and combined double-antibody/polyethylene glycol radioimmunoassays produced no evidence of interference by erythrocyte proteins in the radioimmune reaction. We conclude that erythrocyte proteins act only as low-affinity secondary binders in radioimmunoassay for thyroxin.
三种红细胞蛋白（其中一种被鉴定为血红蛋白）能结合甲状腺激素。我们采用葡聚糖/活性炭放射免疫分析法检测干血斑中的甲状腺素，结果表明，这种结合会因所用缓冲液的不同而有所差异。巴比妥缓冲液、磷酸盐缓冲液和硼酸盐缓冲液比甘氨酸缓冲液和三（羟甲基）甲胺缓冲液能显著增强这种结合。结合不受常用于抑制甲状腺素与血清蛋白结合的试剂的影响。样本储存（温度和时长）与甲状腺素 - 红细胞结合增加之间存在高度显著的非线性直接关系，同时甲状腺素检测浓度也相应降低。然而，采用聚乙二醇以及联合双抗体/聚乙二醇放射免疫分析法对甲状腺素进行连续检测时，未发现红细胞蛋白对放射免疫反应产生干扰的证据。我们得出结论，在甲状腺素放射免疫分析中，红细胞蛋白仅作为低亲和力的二级结合物发挥作用。
