Silva J E, Larsen P R
Science. 1977 Nov 11;198(4317):617-20. doi: 10.1126/science.199941.
An excellent correlation was observed between nuclear triiodothyronine (T3) and the ensuing suppression of thyrotropin (TSH) after a single intravenous injection of T3 to thyroidectomized (hypothyroid) rats. At 1 and 2 hours after injection of thyroxine (T4), in amounts equally potent to the administered T3 in terms of acute suppression of TSH, the same quantities of T3 were found in the pituitary nuclei. Virtually no nuclear T4 was present, and plasma T3 was negligible at these short intervals after T4 injection. These results suggest that suppression of TSH release in hypothyroid rats occurs by interaction of T3 with the nuclear receptor of the thyrotroph. After T4 injection, the T3 found in the nucleus is derived from rapid intrapituitary monodeiodination.
对甲状腺切除（甲状腺功能减退）的大鼠单次静脉注射三碘甲状腺原氨酸（T3）后，观察到细胞核内T3与随后促甲状腺激素（TSH）的抑制之间存在良好的相关性。在注射甲状腺素（T4）后1小时和2小时，就急性抑制TSH而言，给予的T4与T3具有同等效力，此时在垂体细胞核中发现了相同数量的T3。实际上不存在细胞核T4，并且在注射T4后的这些短时间间隔内，血浆T3可忽略不计。这些结果表明，甲状腺功能减退大鼠中TSH释放的抑制是通过T3与促甲状腺细胞的核受体相互作用而发生的。注射T4后，细胞核中发现的T3来源于垂体快速的单碘脱碘作用。
