胰岛细胞多肽激素分泌颗粒释放形式及其转运意义的透射电镜观察

目的观察胰岛的超微结构特点，探讨胰岛细胞多肽激素分泌颗粒的释放形式和转运途径及其功能意义。方法对小鼠胰组织超薄切片，进行透射电镜观察。结果小鼠胰岛散在分布于胰腺小叶之间，主要由A、B两类内分泌细胞组成。胰岛内部和周围存在丰富的有孔型（50nm）毛细血管；毛细淋巴管内皮为开放连接型（0．5～1．5μm），只存在于胰岛周围。胰岛细胞内含大量电子致密的分泌颗粒（200～500nm），常见许多分泌颗粒靠近细胞膜或突出于细胞表面。在胰岛细胞周围的组织间隙内，也常见到与胰岛细胞内相似的分泌颗粒。结论小鼠胰岛细胞多肽激素分泌颗粒连同颗粒被膜整体释放；释放入胰组织液中的多肽激素或分泌颗粒，更易通过淋巴管随淋巴转运，间接进入血液循环而发挥作用。

THE TEM-OBSERVATION OF THE RELEASING PATTERN AND TRANSPORT SIGNIFICANCE OF POLYPEPTIDE HORMONE SECRETORY GRANULES OF PANCREATIC ISLET CELLS

Objective To observe the ultrastructural features of pancreatic islets,to explore the releasing pattern, transport route and functional significance of secretory granules of polypeptide hormone of pancreatic islet cells. Methods The ultrathin sections of mice pancreatic tissue were observed with transmission electron microscope（TEM）. Results The mice pancreatic islets distributed diffusely among the glandular lobules of pancreas,is chiefly composed of A and B endocrine cells. The fenestrated （50 nm） blood capillaries distribute inside and around the pancreatic islets,the lymphatic capillaries in the mice pancreas is opening （0.5-1.5μm） junction of endothelial cells, only exist around the pancreatic islets. There are much secretory granules （200-500 nm） with electron dense substance inside the pancreatic islet cells. Some of secretory granules often close to or protrude from surface of cellular membrane. Many membrane bounded intact secretory granules which were similar to those inside pancreatic islet cells, were seen within connective tissue space. Conclusion The ultrastructural features of mice pancreatic islets indicate that releasing pattern of secretory granules of polypeptide hormone of pancreatic islet cells can be a whole releasing together with granular membrane. The polypeptide hormone or secretory granule released into pancreatic tissue fluid enter lymphatic vessel easily, circulate with lymph, and then enter blood circulation to play its roles.