在鸡胚发育过程中甲状腺激素与靶组织细胞核的结合。

Binding of thyroid hormones by nuclei of target tissues during the chick embryo development.

作者信息

Bellabarba D, Lehoux J G

出版信息

Mech Ageing Dev. 1985 May 31;30(3):325-31. doi: 10.1016/0047-6374(85)90121-6.

Abstract

In the present studies we have compared the ontogeny of the binding of thyroxine (T4) and triiodothyronine (T3) to isolated nuclei from various target tissues of chick embryo. We observed a marked difference between the patterns of Satchard plots, maximal binding capacities (MBC) and association constants (Ka) of T4 and those of T3. Scatchard plots revealed that T4 and T3 had different binding sites. In liver, brain and lung MBCs and Kas of T3 and T4 were rather similar at day 9, but during the following days (12-19) T3 MBCs and Kas showed small changes, whereas T4 MBC markedly increased (4-5-fold) and T4 Ka significantly declined. In liver, for instance, T3 MBC = 395 +/- 19 (day 9) and 489 +/- 66 fmol/mg protein (day 19); T4 MBC = 631 +/- 6.5 (day 9) and 2201 +/- 516 fmol/mg protein (day 19); T4 Ka = 1.92 +/- 0.01 (day 9) and 0.56 +/- 0.21 X 10(8) M-1 (day 19). These data indicate that, during chick embryogenesis, nuclei of target tissues contain multiple T4 binding proteins, but only a single T3 binding site.

摘要

在目前的研究中，我们比较了甲状腺素（T4）和三碘甲状腺原氨酸（T3）与鸡胚各种靶组织分离细胞核的结合个体发生情况。我们观察到T4和T3的Scatchard图模式、最大结合容量（MBC）和结合常数（Ka）之间存在显著差异。Scatchard图显示T4和T3具有不同的结合位点。在肝脏、大脑和肺中，T3和T4的MBC和Ka在第9天时相当相似，但在接下来的几天（12 - 19天），T3的MBC和Ka变化较小，而T4的MBC显著增加（4 - 5倍）且T4的Ka显著下降。例如，在肝脏中，T3的MBC = 395 ± 19（第9天）和489 ± 66 fmol/mg蛋白质（第19天）；T4的MBC = 631 ± 6.5（第9天）和2201 ± 516 fmol/mg蛋白质（第19天）；T4的Ka = 1.92 ± 0.01（第9天）和0.56 ± 0.21×10⁸ M⁻¹（第19天）。这些数据表明，在鸡胚发育过程中，靶组织的细胞核含有多种T4结合蛋白，但只有一个T3结合位点。