Lin T, Haskell J, Vinson N, Terracio L
Biochem Biophys Res Commun. 1986 Jun 30;137(3):950-6. doi: 10.1016/0006-291x(86)90317-7.
Insulin-like growth factor-I (IGF-I) in concentration as low as 10 ng/ml significantly increased basal testosterone formation and 100 ng/ml of IGF-I increased testosterone production more than two fold in primary cultures of purified mature Leydig cells. IGF-I also markedly potentiated hCG-induced testosterone formation in a dose-dependent manner. Furthermore, IGF-I enhanced 8-bromo cyclic AMP induced steroidogenesis and hCG-stimulated cyclic AMP formation. The binding of 125I-IGF-I to purified Leydig cells was linear with a binding affinity of 0.56 +/- 0.07 X 10(9) M-1 and a capacity of 167 +/- 10.2 fmol/mg protein. Insulin and multiplication-stimulating activity were less potent than IGF-I in competing the binding of 125I-IGF-I to purified Leydig cells. This suggests that Leydig cells contain specific type I IGF receptor and IGF-I could modulate Leydig cell steroidogenesis.
在纯化的成熟睾丸间质细胞原代培养物中，低至10纳克/毫升浓度的胰岛素样生长因子-I（IGF-I）能显著增加基础睾酮生成，而100纳克/毫升的IGF-I可使睾酮生成增加两倍以上。IGF-I还以剂量依赖方式显著增强人绒毛膜促性腺激素（hCG）诱导的睾酮生成。此外，IGF-I增强了8-溴环磷酸腺苷（8-bromo cyclic AMP）诱导的类固醇生成以及hCG刺激的环磷酸腺苷生成。125I-IGF-I与纯化的睾丸间质细胞的结合呈线性，结合亲和力为0.56±0.07×10⁹ M⁻¹，结合容量为167±10.2飞摩尔/毫克蛋白质。在竞争125I-IGF-I与纯化的睾丸间质细胞的结合方面，胰岛素和促增殖活性比IGF-I的作用弱。这表明睾丸间质细胞含有特异性I型IGF受体，且IGF-I可调节睾丸间质细胞的类固醇生成。
