Krugman L G, Hershman J M, Chopra I J, Levine G A, Pekary E, Geffner D L, Chua Teco G N
J Clin Endocrinol Metab. 1975 Jul;41(1):70-80. doi: 10.1210/jcem-41-1-70.
To determine the patterns of recovery of the hypothalamic-pituitary-thyroid axis following long-term thyroid hormone therapy, TRH tests were performed on 8 euthyroid nongoitrous patients, 5 euthyroid goitrous patients, and 5 hypothyroid patients while they were taking full doses of thyroid hormone and 3, 7, 10, 14, 17, 21, 28, 35, 42, 49, and 56 days after stopping it. Serum TSH, T3, and T4 were measured before and at multiple intervals over a 4-h period after giving 500 mug TRH iv. In euthyroid non-goitrous patients, the mean duration of suppressed TSH response to TRH (maximum deltaTSH less than 8 muU/ml) was 12 +/- 4 (SE) days after stopping thyroid hormone and the mean time to recovery of normal TSH response to TRH (maximum deltaTSH greater than 8 muU/ml) was 16 +/- 5 days. None of the euthyroid nongoitrous patients ever hyperresponded to TRH; their average maximal deltaTSH was 24.5 +/- 2.2 muU/ml. Serum T4 fell below normal in 4 euthyroid non-goitrous patients, reaching lowest values at 4 to 28 days. While serum T4 was low, deltaTSH was subnormal. Normal increments of T4 and T3 after TRH occurred at 19 +/- 5 and 22 +/- 6 days, respectively. In the 5 goitrous patients, patterns of recovery of pituitary and thyroid function assessed by the same parameters were much less consistent. In the 5 hypothyroid patients, the mean duration of suppressed basal TSH and suppressed deltaTSH was 13 +/- 3 days; mean time to attain a supranormal basal TSH (greater than 8 muU/ml) was 16 +/- 4 days and to reach a supranormal deltaTSH (greater than 38 muU/ml) after TRH was 29 +/- 8 days. Following prolonged thyroid therapy in euthyroid patients, recovery of normal TSH responsiveness to TRH preceded recovery of the normal T3 and T4 response to TRH by 3 to 6 days. Basal serum TSH may be used to differentiate euthyroid from hypothyroid patients 35 days after withdrawal of thyroid therapy; the response to TRH does not improve this differentiation.
为了确定长期甲状腺激素治疗后下丘脑 - 垂体 - 甲状腺轴的恢复模式，对8例甲状腺功能正常且无甲状腺肿的患者、5例甲状腺功能正常的甲状腺肿患者和5例甲状腺功能减退患者进行了促甲状腺激素释放激素（TRH）试验，试验时他们正在服用全剂量甲状腺激素，以及在停药后3、7、10、14、17、21、28、35、42、49和56天进行。静脉注射500μg TRH前及注射后4小时内多个时间点测定血清促甲状腺激素（TSH）、三碘甲状腺原氨酸（T3）和甲状腺素（T4）。在甲状腺功能正常且无甲状腺肿的患者中，停药后TSH对TRH反应受抑制（最大ΔTSH小于8μU/ml）的平均持续时间为12±4（标准误）天，TSH对TRH正常反应恢复（最大ΔTSH大于8μU/ml）的平均时间为16±5天。甲状腺功能正常且无甲状腺肿的患者中无一例对TRH反应过度；他们的平均最大ΔTSH为24.5±2.2μU/ml。4例甲状腺功能正常且无甲状腺肿的患者血清T4降至正常以下，在4至28天达到最低值。当血清T4较低时，ΔTSH低于正常。TRH后T4和T3的正常升高分别在19±5天和22±6天出现。在5例甲状腺肿患者中，用相同参数评估的垂体和甲状腺功能恢复模式不太一致。在5例甲状腺功能减退患者中，基础TSH受抑制和ΔTSH受抑制的平均持续时间为13±3天；达到超正常基础TSH（大于8μU/ml）的平均时间为16±4天，TRH后达到超正常ΔTSH（大于38μU/ml）的平均时间为29±8天。甲状腺功能正常的患者长期接受甲状腺治疗后，TSH对TRH的正常反应恢复比T3和T4对TRH的正常反应恢复早3至6天。停药35天后，基础血清TSH可用于区分甲状腺功能正常和甲状腺功能减退的患者；对TRH的反应并不能改善这种区分。
