Failure of organic iodine enrichment to influence the binding of bovine thyrotropin to rat thyroid tissue.
Failure of organic iodine enrichment to influence the binding of bovine thyrotropin to rat thyroid tissue.
复制标题
有机碘富集未能影响牛促甲状腺素与大鼠甲状腺组织的结合。
作者：
H. Uchimura;S. Amir;S. Ingbar
为了阐明甲状腺中有机碘含量增加导致TSH产生的甲状腺腺苷酸环化酶的刺激受到抑制的机制，研究了碘富集对甲状腺组织中受体与TSH特异性结合的影响。甲状腺有机碘含量的增加是通过在体外将完整缺碘大鼠的甲状腺叶在含碘的培养基中孵育（含或不含TSH）或在体内将碘给予完整缺碘大鼠或切除垂体缺碘大鼠而急性诱导的。然后，使用能够研究先前在大鼠甲状腺组织中证明的bTSH饱和结合位点特性的方法，在从这些腺体和对照腺体制备的组分中评估了125 I标记的牛TSH（bTSH）的特异性结合及其被未标记bTSH的置换。在所采用的模型中，事先提高甲状腺有机碘含量似乎不会影响最大钙离子浓度。
In an effort to clarify the mechanism whereby increases in the thyroid content of organic iodine lead to inhibition of the stimulation of thyroid adenylate cyclase produced by TSH, studies have been conducted of the effect of enrichment with iodine on the specific binding of TSH by receptors in thyroid tissue. Enhancement of thyroid organic iodine content was induced acutely by incubating thyroid lobes of intact iodinedeficient rats in media containing iodide, with or without TSH, in vitro or by administering iodide to intact or hypophysectomized iodine-deficient rats in vivo. Specific binding of 125I-labeled bovine TSH (bTSH) and its displacement by unlabeled bTSH was then assessed in fractions prepared from these and control glands using methods which make possible study of the properties of the saturable binding site for bTSH previously demonstrated in rat thyroid tissue. In none of the models employed did prior enhancement of the thyroid organic iodine content appear to influence either the maximum ca...