Roy S K, Greenwald G S
Department of Obstetrics and Gynecology, University of Nebraska Medical Center, Omaha 68198.
Endocrinology. 1991 Oct;129(4):1903-8. doi: 10.1210/endo-129-4-1903.
FSH stimulates DNA synthesis by hamster preantral follicles both in vivo and in vitro, and the in vitro mitogenic effect of FSH is effectively reproduced by epidermal growth factor (EGF). To determine whether follicular EGF is the intracellular transducer of FSH action on hamster preantral follicles, intact follicles at stages 1 to 7 (stages 1-4 = preantral follicles 1-4 layers of granulosa cells, respectively, and no theca; stages 5-6 = 5-6 and 7-8 layers granulosa cells, respectively, and developing theca; and stage 7 = follicles with incipient antrum) were cultured for 24 h in a serum-free culture medium in the absence or presence of 100 ng FSH, 50 ng EGF, 50 ng transforming growth factor-alpha (TGF alpha), or 1 mumol 8-Br-cAMP and challenged with 50 microliters polyclonal antimurine EGF antiserum; the rate of DNA synthesis was determined by [3H]thymidine incorporation. FSH, EGF, and TGF alpha significantly (P less than 0.05) stimulated follicular DNA synthesis; TGF alpha per se was less effective than either FSH or EGF. However, both FSH- and EGF-induced DNA synthesis was drastically attenuated by EGF antiserum; TGF alpha effect remained undisturbed. Interestingly antibody inhibition of FSH-induced DNA synthesis was totally reversed by coexposure to TGF alpha. Follicular DNA synthesis for most stages was stimulated by Br-cAMP, but the effect was significantly (P less than 0.05) inhibited by EGF antibody. Moreover, follicles at different stages responded to EGF with different latency. These results strongly suggest that FSH-induced follicular DNA synthesis in the hamster is mediated by follicular EGF and the pathway of events is FSH action----cAMP production----EGF synthesis----cell proliferation.
促卵泡激素（FSH）在体内和体外均能刺激仓鼠腔前卵泡的DNA合成，且表皮生长因子（EGF）可有效再现FSH的体外促有丝分裂作用。为确定卵泡EGF是否为FSH作用于仓鼠腔前卵泡的细胞内转导因子，将1至7期的完整卵泡（1 - 4期 = 分别为1 - 4层颗粒细胞的腔前卵泡，无卵泡膜；5 - 6期 = 分别为5 - 6层和7 - 8层颗粒细胞，且卵泡膜正在发育；7期 = 有初始卵泡腔的卵泡）在无血清培养基中培养24小时，培养条件为添加或不添加100 ng FSH、50 ng EGF、50 ng转化生长因子 - α（TGFα）或1 μmol 8 - 溴 - 环磷酸腺苷（8 - Br - cAMP），然后用50微升多克隆抗鼠EGF抗血清进行刺激；通过[³H]胸腺嘧啶核苷掺入法测定DNA合成速率。FSH（促卵泡激素）、EGF（表皮生长因子）和TGFα（转化生长因子 - α）均显著（P < 0.05）刺激卵泡DNA合成；TGFα本身的作用效果不如FSH或EGF。然而，FSH和EGF诱导DNA合成的作用均被EGF抗血清显著减弱；TGFα的作用不受影响。有趣的是，同时暴露于TGFα可完全逆转抗体对FSH诱导DNA合成的抑制作用。大多数阶段的卵泡DNA合成受Br - cAMP刺激，但该作用被EGF抗体显著（P < b 0.05）抑制。此外，不同阶段的卵泡对EGF的反应潜伏期不同。这些结果强烈表明，仓鼠中FSH诱导的卵泡DNA合成是由卵泡EGF介导的，其事件途径为FSH作用→cAMP产生→EGF合成→细胞增殖。
