Murono E P, Washburn A L, Goforth D P, Wu N
Research Service, Dorn Veterans' Hospital, Columbia, SC.
Mol Cell Endocrinol. 1992 Oct;88(1-3):39-45. doi: 10.1016/0303-7207(92)90007-s.
Previous studies have shown that basic fibroblast growth factor (bFGF) can modulate basal and luteinizing hormone/human chorionic gonadotropin (LH/hCG)-stimulated Leydig cell functions. It has not been ascertained whether these actions are due to direct or indirect effects on Leydig cells. To resolve this question, a multi-step procedure was used to isolate highly-purified Leydig cells from immature rats. 125I-bFGF binding studies were performed on cultured cells. Scatchard analysis of the data indicated a single binding site with an apparent Kd of 82 pM and a binding capacity of approximately 2800 sites per cell. Both bFGF and acidic FGF similarly were effective in displacing 125I-bFGF, suggesting that the receptor binds both bFGF and aFGF. However, neither hCG, follicle-stimulating hormone (FSH), insulin, insulin-like growth factor-1 (IGF-1), prolactin, platelet-derived growth factor (PDGF) or epidermal growth factor (EGF) were effective competitors. When binding studies were conducted on cultured testicular interstitial cellular fractions that are normally discarded during Leydig cell purification, bFGF receptors were identified in these fractions. These results demonstrate that bFGF can have direct effects on Leydig cells through specific receptors; however, because other interstitial cell type(s) also have bFGF receptors, they stress the importance of using highly purified cells when evaluating bFGF actions on Leydig cells.
以往的研究表明，碱性成纤维细胞生长因子（bFGF）可调节基础状态以及黄体生成素/人绒毛膜促性腺激素（LH/hCG）刺激下的睾丸间质细胞功能。目前尚未确定这些作用是对睾丸间质细胞的直接作用还是间接作用。为了解决这个问题，我们采用了多步骤程序从未成熟大鼠中分离出高度纯化的睾丸间质细胞。对培养的细胞进行了¹²⁵I-bFGF结合研究。对数据进行Scatchard分析表明存在一个单一结合位点，其表观解离常数（Kd）为82 pM，每个细胞的结合容量约为2800个位点。bFGF和酸性成纤维细胞生长因子（aFGF）在置换¹²⁵I-bFGF方面同样有效，这表明该受体可结合bFGF和aFGF。然而，hCG、促卵泡激素（FSH）、胰岛素、胰岛素样生长因子-1（IGF-1）、催乳素、血小板衍生生长因子（PDGF）或表皮生长因子（EGF）均不是有效的竞争剂。当对在睾丸间质细胞纯化过程中通常被丢弃的培养睾丸间质细胞组分进行结合研究时，在这些组分中鉴定出了bFGF受体。这些结果表明，bFGF可通过特异性受体对睾丸间质细胞产生直接作用；然而，由于其他间质细胞类型也具有bFGF受体，因此强调了在评估bFGF对睾丸间质细胞的作用时使用高度纯化细胞的重要性。
