Chiu S C, Kubota K, Kuzuya N, Ikeda H, Uchimura H, Nagataki S
Acta Endocrinol (Copenh). 1983 May;103(1):68-75. doi: 10.1530/acta.0.1030068.
Mice were injected sc with TSH (0.5 U) at 12 h intervals for 5 days. Groups of mice were sacrificed daily to determine serum T4 and T3 concentrations, 4 h thyroidal 125I uptake, distribution of 125I among thyroidal iodoamino acids, and thyroidal content of T4 and T3. Serum T4 and T3 concentrations increased significantly after the initial injection of TSH and gradually decreased thereafter, reaching initial levels on the 3rd and 4th days, respectively. In contrast to serum hormone levels, thyroidal 125I uptake, incorporation of 125I into T4 and T3 increased significantly on the first day and remained elevated throughout the period of TSH-treatment. Thyroidal T4 content expressed as microgram/mg weight of tissue decreased significantly on the first day and thereafter remained constant. Thyroidal T3 content did not change significantly throughout the experimental period. The differences between thyroidal synthesis and thyroidal contents of T4 and T3 strongly suggest that thyroid hormone secretion is being continuously stimulated. Transient increases in serum T4 and T3 concentrations are probably due to a gradual increase in the rate of peripheral degradation of thyroid hormones. These results suggest that TSH-induced refractoriness in thyroidal iodine metabolism does not appear to exist, at least when TSH is given in vivo for 5 days.
每隔12小时给小鼠皮下注射促甲状腺激素（0.5单位），共注射5天。每天处死一组小鼠，以测定血清甲状腺素（T4）和三碘甲状腺原氨酸（T3）浓度、甲状腺对125I的4小时摄取量、125I在甲状腺碘氨基酸中的分布以及甲状腺中T4和T3的含量。首次注射促甲状腺激素后，血清T4和T3浓度显著升高，此后逐渐下降，分别在第3天和第4天降至初始水平。与血清激素水平相反，甲状腺对125I的摄取、125I掺入T4和T3在第一天显著增加，并在促甲状腺激素治疗期间一直保持升高。以微克/毫克组织重量表示的甲状腺T4含量在第一天显著下降，此后保持恒定。在整个实验期间，甲状腺T3含量没有显著变化。甲状腺T4和T3的合成与甲状腺含量之间的差异强烈表明甲状腺激素分泌受到持续刺激。血清T4和T3浓度的短暂升高可能是由于甲状腺激素外周降解速率逐渐增加所致。这些结果表明，至少在体内给予促甲状腺激素5天时，促甲状腺激素诱导的甲状腺碘代谢不应性似乎不存在。
