Suarez-Quian C A, Oke B O, Radhakrishnan B
Department of Anatomy and Cell Biology, Georgetown University Medical Center, Washington, DC 20007.
Tissue Cell. 1994 Jun;26(3):285-98. doi: 10.1016/0040-8166(94)90015-9.
Epidermal growth factor (EGF), a potent mitogen produced primarily in the submandibular gland of adult male mice, has been implicated in modulating processes known to be of vital importance in the regulation of spermatogenesis. In the present investigation we demonstrate that submandibular gland EGF from adult male mice is indeed capable of displacing radiolabeled EGF from testicular membranes. Scatchard analysis of this binding site reveals that it is of high affinity (Kd = 0.77 nM) and low capacity (Bmax = 8.15 fmol/mg protein). Cross-linking of 125I-EGF to the identical membrane preparation resulted in the SDS-PAGE/autoradiography identification of a single band at approximately 170 kDa. Next, we examined the cellular distribution of the EGF receptor in the testis using biotin-streptavidin immunoperoxidase and employing different antisera probes generated to a conserved sequence of the EGF receptor. The Scatchard and cross-linking data described above, along with the immunocytochemistry results, suggest strongly that there is only one functional binding site for EGF in the adult testis and that this receptor is present in Sertoli and Leydig cells.
表皮生长因子（EGF）是一种主要在成年雄性小鼠颌下腺产生的强效有丝分裂原，它与调节精子发生过程中已知至关重要的过程有关。在本研究中，我们证明成年雄性小鼠颌下腺的EGF确实能够从睾丸膜上置换放射性标记的EGF。对该结合位点的Scatchard分析表明，它具有高亲和力（Kd = 0.77 nM）和低容量（Bmax = 8.15 fmol/mg蛋白质）。将125I-EGF与相同的膜制剂交联，通过SDS-PAGE/放射自显影鉴定出一条约170 kDa的单带。接下来，我们使用生物素-链霉亲和素免疫过氧化物酶，并采用针对EGF受体保守序列产生的不同抗血清探针，研究了EGF受体在睾丸中的细胞分布。上述Scatchard和交联数据，以及免疫细胞化学结果，强烈表明成年睾丸中EGF只有一个功能性结合位点，且该受体存在于支持细胞和间质细胞中。
