Immunocytochemical study of trans-Golgi-network (TGN)-associated protein in salivary acinar cells under varying condition of salivary secretion

用抗小CTP结合蛋白Rab3A、Rab3B、Rab3D、Rab4和Rab6的抗血清和反高尔基网络(TGN)的标志物TGN38，用免疫荧光方法研究了这些Rab蛋白在小鼠和大鼠几个内分泌腺和外分泌腺中的分布。抗Rab3A和Rab6免疫组织化学染色了部分大鼠垂体内分泌细胞，推测Rab3A免疫反应阳性细胞可能是ACTH细胞。抗Rab3A免疫组织化学染色大鼠胰岛多个内分泌细胞。用抗胰腺激素抗体免疫组织化学染色，发现这些免疫染色的细胞是α细胞。相反，抗Rab3D免疫组织化学染色的胰腺腺泡细胞，免疫反应区定位于酶原颗粒区域。在这些材料中已经尝试了Rab3A或Rab3D和TGN38的双重电子显微镜免疫金定位，但电子显微镜没有获得最佳的分辨率。然而，在光镜下发现，这些Rab蛋白的免疫反应定位于分泌颗粒领域。由于Rab与分泌颗粒相关，Rab蛋白可能在调节胞吐作用中发挥作用。

Specific antisera against Rab3A, Rab3B, Rab3D, Rab4, and Rab6, small CTP-binding proteins, and TGN38, a marker of trans-Golgi network (TGN), have been used to examine the distribution of these Rab proteins in several endocrine and exocrine glands of mouse and rat by immunofluorescence method. The anti-Rab3A and Rab6 immunostained some rat pituitary endocrine cells, It is conceivable by these distribution that the Rab3A-immunoreactive cells may be ACTH cells. The anti-Rab3A immunostained exclusively several endocrine cells of pancreatic islets of rat. When cosecutive sections were immunostained with antibodies against pancreatic hormones, these immunostained cells were found to be alpha cells. In contrast, anti-Rab3D immunostained pancreatic acinar cells, and the immunoreacted region localized to the zymogen granule field. Double electron microscopic immunogold localizations for Rab3A or Rab3D and TGN38 have been tried in these materials, but no optimal resolution has not obtained by electron microscope. However, it was found in the light microscopy that these immunoreactive localization of Rab proteins should be in the field of secretion granules. Because of the Rab associated with secretion granules, Rab proteins may play a role in regulated exocytosis.