Koike K, Watanabe H, Hiroi M, Tonosaki A
Department of Obstetrics & Gynecology, Yamagata University School of Medicine, Japan.
J Electron Microsc (Tokyo). 1993 Apr;42(2):94-106.
The gap junction (GJ) of stratum granulosum cells was investigated in growing and mature follicles of the mouse by means of light- and electron-microscopic immunohistochemistry, freeze-fracturing and deep-etching methods. GJ increased in number and size in concert with the progress of follicular maturation and decreased rapidly in the preovulatory mature follicle. GJ membrane showed invagination, most remarkably at 5 h after hCG injection, within the cytoplasm of the granulosum cell. Two types of internalization seemed possible, annular internalization and highly convoluted tubular invagination, both by an actin-mediated mechanism. At least, a part of the internalized GJ membrane seemed to be degraded by a certain lysosomal enzyme (s). Connexin43 (derived from rat cardiac muscle GJ) was indicated to be a constituent of GJ protein in the mouse stratum granulosum cell. There was no GJ particle coexisting with tight junctional strands; by contrast, a formation plaque appeared quite often on granulosum cells at various stages. Such a plaque is presumed to represent a precursor structure of the new GJ of these cells. So far examined, however, the formation plaque failed to show positive reaction against anti-Cx43 antibody.
运用光镜和电镜免疫组织化学、冷冻蚀刻及深度蚀刻方法，对小鼠生长卵泡和成熟卵泡中颗粒层细胞的缝隙连接（GJ）进行了研究。随着卵泡成熟进程，GJ数量增多、尺寸增大，而在排卵前成熟卵泡中迅速减少。在颗粒层细胞胞质内，GJ膜出现内陷，在注射人绒毛膜促性腺激素（hCG）后5小时最为明显。似乎存在两种内吞类型，即环状内吞和高度卷曲的管状内陷，均通过肌动蛋白介导机制进行。至少，部分内化的GJ膜似乎被某种溶酶体酶降解。连接蛋白43（源自大鼠心肌GJ）被证实是小鼠颗粒层细胞中GJ蛋白的一个组成部分。不存在与紧密连接链共存的GJ颗粒；相反，在各个阶段的颗粒层细胞上经常出现形成斑。这种斑被推测代表这些细胞新GJ的前体结构。然而，就目前所检测的情况而言，形成斑对抗Cx43抗体未显示阳性反应。
