Darras V M, Huybrechts L M, Berghman L, Kühn E R, Decuypere E
Laboratory of Comparative Endocrinology, K.U.L., Leuven, Belgium.
Gen Comp Endocrinol. 1990 Feb;77(2):212-20. doi: 10.1016/0016-6480(90)90305-6.
The ontogeny of the effect of chicken growth hormone (c-GH) on the liver 5' monodeiodination (5'-D) activity was studied in chickens starting from 14-day-old embryos until 5-week-old chickens. Ten micrograms of the purified hormone was injected intravenously and after 2 hr, blood and liver samples were taken. In all embryonic stages tested, c-GH stimulated the peripheral thyroxine (T4) to triiodothyronine (T3) conversion as demonstrated by the increased plasma T3 level and liver 5'-D activity while the plasma reverse T3 (rT3) level was decreased. In chicks 1 day after hatching, GH was still able to increase the plasma T3 level and the liver 5'-D activity. However, in 2-day-old chicks, this stimulation had completely disappeared, while the control value of the plasma T3/T4 ratio was considerably higher than the day before. The effect of c-GH injection gradually turned into a decrease of 5'-D activity and plasma T3 in 5- and 7-day-old chicks. Further on, no effect of c-GH could be found in 2- to 4-week-old growing chickens, but in 5-week-old GH-injected animals the plasma T4 and rT3 level decreased again, although no significant effect on T3 or liver 5'-D activity could be demonstrated.
研究了鸡生长激素（c-GH）对鸡肝脏5'单脱碘酶（5'-D）活性影响的个体发生过程，研究对象为14日龄胚胎至5周龄的鸡。静脉注射10微克纯化激素，2小时后采集血液和肝脏样本。在所有测试的胚胎阶段，c-GH均刺激外周甲状腺素（T4）向三碘甲状腺原氨酸（T3）的转化，表现为血浆T3水平升高和肝脏5'-D活性增加，同时血浆反三碘甲状腺原氨酸（rT3）水平降低。在孵化后1天的雏鸡中，GH仍能增加血浆T3水平和肝脏5'-D活性。然而，在2日龄雏鸡中，这种刺激完全消失，而血浆T3/T4比值的对照值比前一天显著升高。在5日龄和7日龄雏鸡中，注射c-GH的效果逐渐转变为5'-D活性和血浆T3降低。进一步研究发现，在2至4周龄的生长鸡中，c-GH没有效果，但在5周龄注射GH的动物中，血浆T4和rT3水平再次降低，尽管对T3或肝脏5'-D活性没有显著影响。
