Bagchi N, Brown T, Shivers B, Mack R E
Endocrinology. 1977 Apr;100(4):1002-7. doi: 10.1210/endo-100-4-1002.
The process of thyroglobulin hydrolysis in mouse thyroid glands labelled in vitro was studied from 2-24 h after they had been maintained in tissue culture. The culture medium was supplemented with mononitrotyrosine to prevent deiodination of iodotyrosines. Hydrolysis of labelled thyroglobulin, under these conditions, led to the release of labelled iodotyrosines and iodothyronines. The rate of formation of these compounds was measured as an index of thyroglobulin hydrolysis (TH). TH was markedly stimulated by TSH. NaI inhibited TSH stimulation of TH at a concentration of 10(-5)M or greater. NaI, at similar concentrations,also markedly diminished or abolished the incorporation of 131I into thyroidal proteins from radioiodide-supplemented media. The addition of various inhibitors of iodination effectively blocked the effect of iodide on TH. In experiments where radioimmunossay was used to measure medium hormone concentrations, the release of unlabelled thyroxine (T4) and triiodothyronine (T3) induced by TSH was found to be significantly decreased in the presence of 10(-4)M NaI. These studies demonstrate that iodide inhibits the hydrolysis of thyroglobulin at or near concentrations which also inhibit iodination of thyroidal proteins. The present data suggest that formation of an iodinated compound is necessary for the effect of iodide. In addition, these studies demonstrate the utility of this in vitro system for the investigation of thyroid physiology.
对体外标记的小鼠甲状腺在组织培养中培养2至24小时后甲状腺球蛋白水解过程进行了研究。培养基中添加了单硝基酪氨酸以防止碘酪氨酸脱碘。在这些条件下，标记甲状腺球蛋白的水解导致标记碘酪氨酸和碘甲状腺原氨酸的释放。这些化合物的形成速率作为甲状腺球蛋白水解（TH）的指标进行测定。促甲状腺激素（TSH）显著刺激TH。碘化钠（NaI）在浓度为10^(-5)M或更高时抑制TSH对TH的刺激。相似浓度的NaI也显著减少或消除了131I从补充放射性碘的培养基掺入甲状腺蛋白的过程。添加各种碘化抑制剂有效地阻断了碘化物对TH的作用。在使用放射免疫测定法测量培养基激素浓度的实验中，发现在存在10^(-4)M NaI的情况下，TSH诱导的未标记甲状腺素（T4）和三碘甲状腺原氨酸（T3）的释放显著减少。这些研究表明，碘化物在抑制甲状腺蛋白碘化的浓度或接近该浓度时抑制甲状腺球蛋白的水解。目前的数据表明，形成一种碘化化合物对于碘化物的作用是必要的。此外，这些研究证明了该体外系统在甲状腺生理学研究中的实用性。
