Kokesová H, Langer P, Gschwendtová K, Sadlon J, Bukovská M
Endocrinol Exp. 1977;11(2):91-8.
Comparison of Preventive Effect of T3 and T4 on Thyroxine Release from Thyroid Induced by Endogenous TSH after TRH Injection. Endocrinologia Experimentalis 11, 91-98, 1977. The technique of frequent blood sampling through polyethylene tubings inserted into blood vessels while maintaining isovolemia was used in pentobarbiturate anaesthetized rats weighing 250--300 g. The animals were fed low iodine diet for 4 weeks and injected 125I- (5 microgram Ci per animal daily) for 6 days begining from 8th day before the experiment. The effect of 25 microgram TRH injected through a cannula inserted into carotid artery in cranial direction was evaluated as per cent increase of labelled thyroxine in plasma at 120 min after the injection compared to its level at 30 min. Moreover, the inhibitory effect of various doses of thyroxine (T4; 5, 20 and 80 nmol kg-1) and triiodothyronine (T3; 1.25 and 5 nmol kg-1) injected i.v. at the intervals of 10, 20, 30, 60 and 180 min prior to TRH was investigated. It was found that the effect was time dependent, being negligible after 10 or 20 min, while after 60 and 180 min the increase of labelled T4 after TRH was fully prevented by 20 and 80 nmol T4 kg-1 and by 5 nmol T3 kg-1. The other doses (i. e. 5 nmol T4 kg-1 and 1.25 nmol T3 kg-1) were without effect. Thus, T3 was found to be significantly more active than equimolar doses of T4.
TRH注射后T3和T4对内源性TSH诱导的甲状腺甲状腺素释放的预防作用比较。《实验内分泌学》11卷，91 - 98页，1977年。在体重250 - 300克的戊巴比妥麻醉大鼠中，采用通过插入血管的聚乙烯管频繁采血并维持血容量恒定的技术。动物喂食低碘饮食4周，并从实验前第8天开始连续6天注射125I（每只动物每天5微克居里）。通过向颅侧插入颈动脉的套管注射25微克TRH的效果，以注射后120分钟时血浆中标记甲状腺素相对于30分钟时的水平增加的百分比来评估。此外，研究了在TRH注射前10、20、30、60和180分钟静脉注射不同剂量甲状腺素（T4；5、20和80纳摩尔/千克）和三碘甲状腺原氨酸（T3；1.25和5纳摩尔/千克）的抑制作用。结果发现，这种作用具有时间依赖性，在10或20分钟后可忽略不计，而在60和180分钟后，20和80纳摩尔T4/千克以及5纳摩尔T3/千克可完全阻止TRH注射后标记T4的增加。其他剂量（即5纳摩尔T4/千克和1.25纳摩尔T3/千克）则无作用。因此，发现T3比等摩尔剂量的T4活性明显更高。
