Neylan D, Smyth P P
Clin Endocrinol (Oxf). 1982 Nov;17(5):479-87. doi: 10.1111/j.1365-2265.1982.tb01615.x.
The thyroid stimulators TSH and thyroid stimulating immunoglobulins (TSI) have previously been distinguished in a cytochemical section bioassay (CBA) by the different times at which they caused maximum increase of lysosomal membrane permeability within guinea-pig thyroid follicular cells. The present study demonstrates that the times at which maximum stimulation occurs in the assay depends not only on the type (TSH or TSI) but also on the concentration of the stimulator. At higher concentrations of stimulator earlier times of maximum stimulation were observed for both TSH and TSI. When both stimulators were simultaneously present in plasma at higher concentrations a single peak of stimulatory activity occurred. Neutralization studies using specific antisera revealed that the single peak represented a merging of TSH and TSI peaks. These findings explain the lack of parallelism to the standard curve seen at higher concentrations of TSH or TSI in the CBA. They emphasize the necessity of measuring plasma samples at a variety of dilutions in order to achieve parallelism and to avoid intra-assay interference between TSH and TSI. When these conditions are observed CBA can be used to detect TSH and TSI with extreme sensitivity even when both are simultaneously present in plasma.
甲状腺刺激素促甲状腺激素（TSH）和甲状腺刺激免疫球蛋白（TSI）以前在细胞化学切片生物测定法（CBA）中通过它们在豚鼠甲状腺滤泡细胞内引起溶酶体膜通透性最大增加的不同时间来区分。本研究表明，该测定法中最大刺激出现的时间不仅取决于刺激素的类型（TSH或TSI），还取决于刺激素的浓度。在较高浓度的刺激素下，TSH和TSI的最大刺激时间都更早出现。当两种刺激素同时以较高浓度存在于血浆中时，会出现一个单一的刺激活性峰值。使用特异性抗血清的中和研究表明，该单一峰值代表TSH和TSI峰值的合并。这些发现解释了在CBA中较高浓度的TSH或TSI时与标准曲线缺乏平行性的现象。它们强调了在多种稀释度下测量血浆样本以实现平行性并避免TSH和TSI之间的测定内干扰的必要性。当遵循这些条件时，即使TSH和TSI同时存在于血浆中，CBA也可用于极其灵敏地检测它们。
