Endo K
Nihon Naibunpi Gakkai Zasshi. 1979 Oct 20;55(10):1249-60. doi: 10.1507/endocrine1927.55.10_1249.
The radioreceptor assay system for TSH is considered to be useful in quantitating the hormone and analyzing the mechanism of its action. The assay was established, and the interaction of abnormal thyroid stimulators in Graves' patients was evaluated in this assay system. A 10,000xg fraction of human thyroid homogenates was used as the receptor. Human TSH supplied from NIH was iodinated by using lactoperoxidase. The binding of 125I-TSH to the receptor was small, and 125I-TSH was further purified by the receptor binding. The receptor (25mg equivalent), purified 125I-TSH, and standard TSH or a sample were incubated at 37 degrees C for 60 min in a final volume of 300 microliters. The binding of 125I-TSH to the receptor was time- and temperature-dependent with optimal binding under the conditions described above. The binding was completely inhibited by the addition of human, bovine and ovine TSH and partially inhibited by high concentrations of HCG, FSH-LH. However, there was no cross reactivity with insulin, prostaglandin E1, E2, T3, T4 and Nal. The assay was sensitive enough to detect 5 to 50 microU of TSH. The amount of TSH bound to the receptor was almost parallel to the TSH concentration which is necessary to stimulate human thyroid adenylate cyclase activity. Studies of dissociation kinetics and Scatchard plot indicated that there were two classes of TSH receptors in the human thyroid. A higher association constant was calculated as 1.5 x 10(8)M-1. LATS-IgG from a patient with Graves' disease completely inhibited the binding of 125I-TSH to the receptor, and studies of Lineweaver-Burk, plot suggested that TSH and LATS-IgG shared common binding sites. The radioreceptor assay of TSH appears to be useful in evaluating the abnormal thyroid stimulators present in Graves' disease.
促甲状腺激素（TSH）的放射受体分析系统被认为在定量该激素及分析其作用机制方面很有用。建立了该分析方法，并在此分析系统中评估了格雷夫斯病（Graves病）患者体内异常甲状腺刺激物的相互作用。用人甲状腺匀浆的10,000xg 级分作为受体。使用乳过氧化物酶对美国国立卫生研究院（NIH）提供的人促甲状腺激素进行碘化。125I-TSH与受体的结合量较少，通过受体结合对125I-TSH进行进一步纯化。将受体（相当于25mg）、纯化的125I-TSH以及标准促甲状腺激素或样品在37℃下于300微升的终体积中孵育60分钟。125I-TSH与受体的结合具有时间和温度依赖性，在上述条件下具有最佳结合。加入人、牛和羊促甲状腺激素可完全抑制该结合，高浓度的人绒毛膜促性腺激素（HCG）、促卵泡激素-促黄体生成素（FSH-LH）可部分抑制该结合。然而，与胰岛素、前列腺素E1、E2、三碘甲状腺原氨酸（T3）、甲状腺素（T4）和碘化钠无交叉反应。该分析方法灵敏度足以检测5至50微单位的促甲状腺激素。与受体结合的促甲状腺激素量几乎与刺激人甲状腺腺苷酸环化酶活性所需的促甲状腺激素浓度平行。解离动力学和Scatchard图研究表明，人甲状腺中有两类促甲状腺激素受体。计算出较高的缔合常数为1.5×10(8)M-1。来自格雷夫斯病患者的长效甲状腺刺激素-免疫球蛋白G（LATS-IgG）完全抑制125I-TSH与受体的结合，Lineweaver-Burk图研究表明促甲状腺激素和LATS-IgG共用共同的结合位点。促甲状腺激素的放射受体分析似乎在评估格雷夫斯病中存在的异常甲状腺刺激物方面很有用。
