Andrology Center, Peking University First Hospital, Peking University, Beijing 100034, China.
Asian J Androl. 2011 Nov;13(6):881-8. doi: 10.1038/aja.2011.85. Epub 2011 Aug 8.
Late-onset hypogonadism (LOH) is closely related to secondary androgen deficiency in aged males, but the mechanism remains unclear. In this study, we found that reduced testosterone production in aged rat Leydig cells is associated with decreased autophagic activity. Primary rat Leydig cells and the TM3 mouse Leydig cell line were used to study the effect of autophagic deficiency on Leydig cell testosterone production. In Leydig cells from young and aged rats, treatment with wortmannin, an autophagy inhibitor, inhibited luteinising hormone (LH)-stimulated steroidogenic acute regulatory (StAR) protein expression and decreased testosterone production. In contrast, treatment with rapamycin, an autophagy activator, enhanced LH-stimulated steroidogenesis in Leydig cells from aged, but not young, rats. Intracellular reactive oxygen species (ROS) levels were increased in both young and aged Leydig cells treated with wortmannin but decreased only in aged Leydig cells treated with rapamycin. Furthermore, an increased level of ROS, induced by H(2)O(2), resulted in LH-stimulated steroidogenic inhibition. Finally, knockdown of Beclin 1 decreased LH-stimulated StAR expression and testosterone production in TM3 mouse Leydig cells, which were associated with increased intracellular ROS level. These results suggested that autophagic deficiency is related to steroidogenic decline in aged rat Leydig cells, which might be influenced by intracellular ROS levels.
迟发性性腺功能减退症（LOH）与老年男性继发性雄激素缺乏密切相关，但机制尚不清楚。在本研究中，我们发现衰老大鼠睾丸间质细胞睾酮生成减少与自噬活性降低有关。原代大鼠睾丸间质细胞和 TM3 小鼠睾丸间质细胞瘤系用于研究自噬缺陷对睾丸间质细胞睾酮生成的影响。在年轻和衰老大鼠的睾丸间质细胞中，用自噬抑制剂渥曼青霉素处理可抑制黄体生成素（LH）刺激的类固醇急性调节蛋白（StAR）蛋白表达，并减少睾酮生成。相反，用自噬激活剂雷帕霉素处理可增强衰老大鼠但不能增强年轻大鼠 LH 刺激的睾丸间质细胞类固醇生成。用渥曼青霉素处理的年轻和衰老的睾丸间质细胞中细胞内活性氧（ROS）水平均升高，但仅在用雷帕霉素处理的衰老的睾丸间质细胞中降低。此外，H2O2 诱导的 ROS 水平增加导致 LH 刺激的类固醇生成抑制。最后，Beclin 1 的敲低降低了 TM3 小鼠睾丸间质细胞中 LH 刺激的 StAR 表达和睾酮生成，这与细胞内 ROS 水平的增加有关。这些结果表明，自噬缺陷与衰老大鼠睾丸间质细胞的类固醇生成下降有关，这可能受细胞内 ROS 水平的影响。
