Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada.
Can J Physiol Pharmacol. 2013 Feb;91(2):157-64. doi: 10.1139/cjpp-2012-0385. Epub 2013 Feb 25.
Connexin43 has been recognized as forming gap junctions in Leydig cells. However, previous work has shown that mouse Leydig cells lacking this connexin do not suffer any limitation of their ability to produce testosterone when stimulated with luteinizing hormone. The objective of this study was to identify additional connexins in mouse Leydig cells that could be required for steroidogenesis. A reverse transcription - polymerase chain reaction screen involving isolated adult Leydig cells identified connexin36 and connexin45 as expressed along with connexin43. Treatment of dissociated testes with carbenoxolone, a nonspecific blocker of gap junctional coupling, significantly reduced testosterone output as did treatment with quinine, which disrupts coupling provided by connexin36 and connexin45 gap junctions but not those composed of connexin43, indicating that either or both of connexins 36 and 45 could be involved in supporting Leydig cell steroidogenesis. Immunolabeling of adult mouse testis sections confirmed the localization of connexin36 along with connexin43 in Leydig cell gap junctions but not connexin45, which is distributed throughout the cells. It was concluded that connexin36, connexin43, and connexin45 are coexpressed in Leydig cells with connexins 36 and 43 contributing to gap junctions. The role of connexin45 remains to be elucidated.
间隙连接蛋白 43 已被确认为形成 Leydig 细胞中的缝隙连接。然而，先前的工作表明，缺乏这种连接蛋白的小鼠 Leydig 细胞在受到黄体生成素刺激时，其产生睾酮的能力不会受到任何限制。本研究的目的是鉴定小鼠 Leydig 细胞中可能需要用于类固醇生成的其他连接蛋白。涉及分离的成年 Leydig 细胞的反转录-聚合酶链反应筛选鉴定出间隙连接蛋白 36 和 45 与间隙连接蛋白 43 一起表达。用非特异性缝隙连接偶联阻断剂 carbenoxolone 处理分离的睾丸，显著降低了睾酮的产生，而 quinine 的处理也是如此，它破坏了由间隙连接蛋白 36 和 45 形成的偶联，但不破坏由间隙连接蛋白 43 形成的偶联，表明间隙连接蛋白 36 和 45 中的一种或两种都可能参与支持 Leydig 细胞类固醇生成。成年小鼠睾丸切片的免疫标记证实了间隙连接蛋白 36 与间隙连接蛋白 43 在 Leydig 细胞缝隙连接中的定位，但不是间隙连接蛋白 45，后者分布在细胞中。结论是，间隙连接蛋白 36、43 和 45 在 Leydig 细胞中共同表达，间隙连接蛋白 36 和 43 参与缝隙连接。间隙连接蛋白 45 的作用仍有待阐明。
