Singh A K, Song R H, Frankfater A F, Leehey D J
Department of Medicine, Loyola-Hines Medical Center, Maywood, Ill., USA.
Exp Nephrol. 1995 Nov-Dec;3(6):355-61.
Epidermal growth factor (EGF) is a growth-promoting cytokine which acts in a paracrine and autocrine fashion on epithelial cells of various tissues. Although previously demonstrated, we have now confirmed the presence of EGF receptors in cultured glomerular epithelial cells (GEC) using radioligand binding studies. Further, the biochemical consequences of EGF receptor activation in this cell type were investigated. In the presence of exogenous EGF, attachment of GEC to plastic was enhanced in a dose-dependent (0.62-10 ng/ml range) manner. At 10 ng/ml of EGF, cell attachment was 5 times higher than in controls. After attachment, there was a 3-fold increase in cell proliferation rate in the presence of 10 ng/ml of EGF. Cells which multiplied and reached confluency in the presence of EGF were 80% larger in volume than in controls. In the presence of EGF, a 70% maximal increase in de novo protein synthetic activity as tested by 3H-leucine incorporation was observed in the dose range of 0.62-10 ng/ml. Further, a dose-dependent increase in extracellular type IV collagenase (gelatinase) as well as in intracellular cathepsins B and D (150 and 260% of control, respectively) activities were noted. It is concluded that GEC respond to exogenous EGF by increasing their protein synthetic rate as well as their catabolic rate, thus resulting in enhanced turnover of macromolecules.
表皮生长因子（EGF）是一种促进生长的细胞因子，以旁分泌和自分泌方式作用于各种组织的上皮细胞。尽管此前已有相关报道，但我们现在通过放射性配体结合研究证实了培养的肾小球上皮细胞（GEC）中存在EGF受体。此外，还研究了这种细胞类型中EGF受体激活的生化后果。在外源性EGF存在的情况下，GEC与塑料的附着以剂量依赖性（0.62 - 10 ng/ml范围）方式增强。在10 ng/ml的EGF作用下，细胞附着比对照组高5倍。附着后，在10 ng/ml的EGF存在下，细胞增殖率增加了3倍。在EGF存在下增殖并达到汇合的细胞体积比对照组大80%。在EGF存在下，在0.62 - 10 ng/ml的剂量范围内，通过3H - 亮氨酸掺入测试的从头蛋白质合成活性最大增加了70%。此外，还观察到细胞外IV型胶原酶（明胶酶）以及细胞内组织蛋白酶B和D的活性呈剂量依赖性增加（分别为对照组的150%和260%）。结论是，GEC通过提高其蛋白质合成速率以及分解代谢速率对外源性EGF作出反应，从而导致大分子周转增强。
