Nathaniel E J, Nathaniel D R, Nathaniel L M, Burt S, Panfili F
Department of Anatomy, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
Exp Neurol. 1988 Jul;101(1):1-16. doi: 10.1016/0014-4886(88)90060-x.
The reversibility of the effects of propylthiouracil induced neonatal hypothyroidism by daily subcutaneous injections of L-thyroxine (T4) was investigated in the rat. Four groups of rat pups were used in this experiment: Group I (control) received equivalent amounts of saline subcutaneously; Group II (hypothyroid) received propylthiouracil injections daily; Group III (T4-14) are hypothyroid rats who received daily T4 replacement therapy (2.5 micrograms/day) subcutaneously starting on Day 14; Group IV (T4-21) are also hypothyroid rats whose T4 replacement therapy (2.5 micrograms/day) was started on Day 21. The four parameters studied were body length, body weight, brain weight, and cerebellar weight in these four groups of animals at 4, 7, 10, 14, 21, 28, 35, and 42 postnatal days. A minimum of eight animals were studied for each time sequence. The present study clearly indicated the beneficial effect of T4 therapy on the length and body weight of the hypothyroid animals, whether therapy was started at Postnatal Day 14 or 21. In addition, a more important finding of this study was the significant increase in brain and cerebellar weights of T4-treated animals compared to the hypothyroid animals, this beneficial effect being more striking in the T4-14 group when compared to that in the T4-14 animals.
通过每日皮下注射L-甲状腺素（T4）来研究丙硫氧嘧啶诱导的新生大鼠甲状腺功能减退症的效应的可逆性。本实验使用了四组幼鼠：第一组（对照组）皮下注射等量的生理盐水；第二组（甲状腺功能减退组）每日注射丙硫氧嘧啶；第三组（T4 - 14组）是甲状腺功能减退大鼠，从出生第14天开始每日皮下接受T4替代疗法（2.5微克/天）；第四组（T4 - 21组）也是甲状腺功能减退大鼠，其T4替代疗法（2.5微克/天）从出生第21天开始。研究的四个参数是这四组动物在出生后第4、7、10、14、21、28、35和42天的体长、体重、脑重和小脑重。每个时间序列至少研究八只动物。本研究清楚地表明，无论治疗是在出生后第14天还是第21天开始，T4治疗对甲状腺功能减退动物的体长和体重都有有益作用。此外，本研究一个更重要的发现是，与甲状腺功能减退动物相比，接受T4治疗的动物的脑重和小脑重显著增加，与T4 - 21组动物相比，这种有益作用在T4 - 14组中更显著。
