Wartofsky L, Dimond R C, Noel G L, Frantz A G, Earll J M
J Clin Endocrinol Metab. 1976 Mar;42(3):443-58. doi: 10.1210/jcem-42-3-443.
Previous investigators have shown that daily administration of TRH to normal individuals leads to diminishing TSH responses which were believed due to rising serum T3 with subsequent feedback inhibition of the pituitary. Patients with primary hypothyroidism were examined in the present study to test this hypothesis, since their T3 cannot increase after TRH. Bi-daily TRH (100 mug) was given to 4 patients for 3 consecutive days, and repeated on a 4th day following oral T3 (50 mug). TSH and PRL responses were unchanged during these 3days of serial TRH and were unaltered by T3 administration on the fouth day. In 5 other hypothyroid subjects studied before and during 3 consecutive days of T3 administration, TSH but not PRL responses to TRH appeared to decrease slowly but progressively. These observations led us to re-examine TRH responses in normal subjects given T3, since other workers had reported that 50 mug T3 completely abolished TSH response. Responses to TRH in 11 normals on a control day were compared to those observed 1 hour after oral T3. In spite of marked increases in serum T3, there was no significant difference between the mean TSH responses of the two studies.
先前的研究人员表明，对正常个体每日给予促甲状腺激素释放激素（TRH）会导致促甲状腺激素（TSH）反应减弱，这被认为是由于血清三碘甲状腺原氨酸（T3）升高，随后对垂体产生反馈抑制所致。在本研究中，对原发性甲状腺功能减退患者进行了检查，以验证这一假设，因为他们在给予TRH后T3无法升高。对4例患者连续3天每日两次给予TRH（100微克），并在口服T3（50微克）后的第4天重复给药。在连续3天给予TRH期间，TSH和催乳素（PRL）反应未发生变化，且在第4天给予T3后也未改变。在另外5例甲状腺功能减退受试者中，在连续3天给予T3之前和期间进行研究，发现他们对TRH的TSH反应而非PRL反应似乎缓慢但逐渐降低。这些观察结果促使我们重新检查给予T3的正常受试者的TRH反应，因为其他研究人员报告称50微克T3可完全消除TSH反应。将11名正常人在对照日对TRH的反应与口服T3 1小时后观察到的反应进行比较。尽管血清T3显著升高，但两项研究的平均TSH反应之间无显著差异。
