Sakly M, Koch B
Mol Cell Endocrinol. 1982 Sep;28(1):27-35. doi: 10.1016/0303-7207(82)90038-7.
The present study was aimed at characterizing the deficiency of the glucocorticoid-receptor system in the immature pituitary gland of neonatal rats. Under conditions of both constant protein and DNA concentrations, [3H]dexamethasone binding to nuclei was significantly lower in the immature, compared with the mature, glands, despite the comparable density of receptor sites. Chromatography on DEAE-Sephacel columns revealed the failure of the neonatal receptor to form stable activated complexes, although the dissociation of tracer from binding sites, as well as the magnitude of receptor activation, remained closely similar to those found for the adult binder. Also, a striking observation was that the immature receptor exhibited the property of forming more than twice as much inactive aggregate as the mature component, when heat-activated in presence of KCl. It thus seems that development of full expression of glucocorticoid-binding activity in the pituitary involves qualitative changes of both the receptor molecules and the cytoplasmic environment, that tend to enhance stability of the activated form of the binder.
本研究旨在表征新生大鼠未成熟垂体中糖皮质激素受体系统的缺陷。在蛋白质和DNA浓度恒定的条件下，尽管受体位点密度相当，但与成熟腺体相比，未成熟腺体中[3H]地塞米松与细胞核的结合显著降低。DEAE-葡聚糖凝胶柱层析显示，新生受体无法形成稳定的活化复合物，尽管示踪剂从结合位点的解离以及受体活化程度与成年结合剂的情况仍非常相似。此外，一个引人注目的观察结果是，当在KCl存在下进行热激活时，未成熟受体形成的无活性聚集体是成熟组分的两倍多。因此，垂体中糖皮质激素结合活性的充分表达似乎涉及受体分子和细胞质环境的质的变化，这些变化倾向于增强结合剂活化形式的稳定性。
