Glucocorticoid-mediated alteration in growth factor binding and action: analysis of the binding change.
Glucocorticoid-mediated alteration in growth factor binding and action: analysis of the binding change.
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糖皮质激素介导的生长因子结合和作用的改变：结合变化的分析。
DOI：
10.1002/jss.400090108
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发表时间：
1978
期刊：
影响因子：
--
通讯作者：
D. Cunningham
中科院分区：
文献类型：
--
作者：
J. Baker;D. Cunningham
糖皮质激素类似物地塞米松（DX）的人成纤维细胞的无血清培养物的加入引起了对表皮生长因子（EGF）的促有丝分裂反应的两倍增强，虽然DX本身不是促有丝分裂的。研究表明DX还增加了125I-EGF的细胞结合，这表明了这种效应的基础。DX仅在低生理浓度的该多肽下增加细胞结合125I-EGF的能力。因此，数据从125 I-EGF结合细胞孵育没有DX产生线性Scatchard图，而数据从125 I-EGF结合DX处理的细胞导致向上曲线Scatchard图。125 I-EGF与细胞表面和细胞质的结合的测量表明，这种结合变化涉及细胞表面EGF受体的改变。结合变化似乎不涉及EGF受体之间的负合作相互作用，也不涉及受体数量的变化。这种结合的改变可以用DX将25 - 30%的细胞表面EGF受体转化为亲和力增加四倍的形式的模型来解释。
The addition of the glucocorticoid analog dexamethasone (DX) to serum-free cultures of human fibroblasts caused a twofold enhancement of the mitogenic response to epidermal growth factor (EGF), although DX by itself was not mitogenic. A basis for this effect was suggested by studies showing that DX also increased the cellular binding of 125I-EGF. DX increased the ability of the cells to bind 125I-EGF only at low physiological concentrations of this polypeptide. Thus, data from 125 I-EGF binding to cells incubated without DX produced a linear Scatchard plot, whereas the data from 125I-EGF binding to DX-treated cells led to an upwardly curvilinear Scatchard plot. Measurements of 125I-EGF association with the cell surface and cytoplasm indicated that this binding change involved an alteration of cell surface EGF receptors. The binding change appeared not to involve negatively cooperative interactions between EGF receptors, nor a change in the number of receptors. The binding alteration could be explained by a model in which DX converted 25--30% of the cell surface EGF receptors to a form having a fourfold increased affinity.