The current study in wall lizards Hemidactylus flaviviridis was designed to ascertain that Leydig cells utilize testicular macrophage-derived 25-hydroxycholesterol (25-HC) for steroidogenesis. Leydig cells (LC) collected from regressed testes when incubated with 25-HC that was obtained from HPLC-eluted fraction of testicular macrophage-conditioned medium (TMCM), lyophilized and reconstituted in culture medium (0.5 µg/ml/well), produced considerably higher amount of testosterone. A similar observation was made when Leydig cells were incubated with varying concentrations of commercial 25-HC. Testosterone production by LC increased in a concentration-dependent manner. Taken together, it is evident that LC utilize 25-HC as a substrate for testosterone biosynthesis. To examine the gonadotropic regulation of steroid biosynthesis utilizing 25-HC as substrate, ovine follicle-stimulating hormone (FSH) that regulates both the testicular functions in lizards was used. Leydig cells were incubated with combinations of FSH and 25-HC as follows: 0 h FSH + 12 h 25-HC, 0 h 25-HC + 12 h FSH. As compared to respective controls, a marked increase in testosterone production was observed in response to FSH indicating that gonadotropin up-regulates uptake of 25-HC as a substrate for testosterone biosynthesis.

目前对壁蜥的研究Hemidactylus flaviviridis旨在确定 Leydig 细胞利用睾丸巨噬细胞衍生的 25-羟基胆固醇 (25-HC) 进行类固醇生成。当与从睾丸巨噬细胞条件培养基 (TMCM) 的 HPLC 洗脱部分获得的 25-HC 孵育时，从退化的睾丸中收集的睾丸间质细胞 (LC)，冻干并在培养基中重组 (0.5 µg/ml/孔)，产生大量睾酮含量较高。当 Leydig 细胞与不同浓度的商业 25-HC 一起温育时，也有类似的观察结果。LC 产生的睾酮以浓度依赖性方式增加。总之，很明显 LC 利用 25-HC 作为睾酮生物合成的底物。为了检查利用 25-HC 作为底物的类固醇生物合成的促性腺激素调节，使用调节蜥蜴睾丸功能的绵羊卵泡刺激素 (FSH)。Leydig 细胞与 FSH 和 25-HC 的组合孵育如下：0 h FSH + 12 h 25-HC、0 h 25-HC + 12 h FSH。与各自的对照相比，观察到响应于 FSH 的睾酮产生显着增加，这表明促性腺激素上调了作为睾酮生物合成底物的 25-HC 的摄取。