Shikone T, Yamoto M, Nakano R
Department of Obstetrics and Gynecology, Wakayama Medical College, Japan.
Endocrinology. 1992 Sep;131(3):1063-8. doi: 10.1210/endo.131.3.1324147.
In the present study we examined the existence of receptors for basic fibroblast growth factor (bFGF) and its regulation in rat granulosa cells. The binding of labeled bFGF to rat granulosa cells was dose-dependently displaced by unlabeled bFGF, but not other growth factors. FSH induced a dose-dependent increase in specific binding for bFGF to cultured rat granulosa cells. FSH treatment did not change the binding affinity (Kd, 2.8-3.0 x 10(-10) M) of the bFGF receptor, but increased the total number of bFGF-binding sites, whereas treatment with several steroid hormones had no effect on the specific binding of bFGF. Since cycloheximide, a protein synthesis inhibitor, inhibited the increase in bFGF binding induced by FSH, it is suggested that protein synthesis might be involved in the FSH stimulation of bFGF receptor induction. Furthermore, bFGF stimulated tissue plasminogen activator activity in a dose-dependent manner, and FSH-primed granulosa cells were more responsive to bFGF action, with a decrease in the ED50 from 5.0 to 1.5 ng/ml. The antibody against human bFGF neutralized the stimulatory effect of bFGF on tissue plasminogen activator secretion. The present study suggests that FSH induces functional receptors for bFGF in granulosa cells and that bFGF may play a role in the process of differentiation under the influence of FSH.
在本研究中，我们检测了大鼠颗粒细胞中碱性成纤维细胞生长因子（bFGF）受体的存在及其调控情况。标记的bFGF与大鼠颗粒细胞的结合可被未标记的bFGF剂量依赖性地取代，但不能被其他生长因子取代。促卵泡激素（FSH）可使培养的大鼠颗粒细胞对bFGF的特异性结合呈剂量依赖性增加。FSH处理并未改变bFGF受体的结合亲和力（解离常数Kd为2.8 - 3.0×10⁻¹⁰ M），但增加了bFGF结合位点的总数，而几种甾体激素处理对bFGF的特异性结合没有影响。由于蛋白质合成抑制剂环己酰亚胺可抑制FSH诱导的bFGF结合增加，提示蛋白质合成可能参与FSH对bFGF受体诱导的刺激作用。此外，bFGF以剂量依赖性方式刺激组织纤溶酶原激活物活性，且FSH预处理的颗粒细胞对bFGF的作用更敏感，半数有效浓度（ED50）从5.0 ng/ml降至1.5 ng/ml。抗人bFGF抗体可中和bFGF对组织纤溶酶原激活物分泌的刺激作用。本研究提示，FSH可诱导颗粒细胞产生功能性bFGF受体，且bFGF可能在FSH影响下的分化过程中发挥作用。
