Analysis of structure and function of folliculo-stellate cell in the anterior pituairy gland

垂体前叶中的滤泡星状细胞（FS细胞）被描述为星形细胞，其细胞分裂过程在相邻的腺泡产生细胞之间延伸并包围它们。FS细胞S-100蛋白和GFAP免疫细胞化学染色阳性，FS细胞胞质内含有分泌颗粒，与正常细胞有明显区别。以往的研究表明，FS细胞对邻近的腺细胞起支持作用。为研究垂体前叶功能，我们建立了一种新的垂体瘤FS细胞系（TtT/GF）。本研究应用TtT/GF技术和去势及衰老动物垂体前叶FS细胞的功能和结构进行了研究。获得的结果如下。1)将TtT/GF细胞和生长激素分泌型垂体瘤细胞系（MtT/S）同时移植于裸鼠体内，每只动物均产生较大的生长激素分泌瘤。相比之下，当裸鼠单独植入MtT/S细胞或与成纤维细胞一起植入时，要么没有肿瘤形成，要么形成非常小的垂体肿瘤。TtT/GF细胞单独移植无肿瘤发生，提示TtT/GF可能通过分泌生长因子或调控微环境如血管生成等途径促进裸鼠垂体肿瘤的形成。2)FS细胞在衰老动物中产生大量含胶体的卵泡。脑垂体湿重比幼龄动物大4倍。有意思的是，催乳素细胞特异性地出现在这些卵泡周围，提示催乳素细胞增殖与衰老动物FS细胞之间存在一定的关系。3)去势后FS细胞的数量与LH细胞的增生成正比，提示FS细胞也刺激去势动物的去势细胞增殖。

Folliculo-stellate cells (FS cells) in the anterior pituitary gland have been described as star-shaped cells with cytopolasmic processes extending between and surrounding neighboring glandular hormone-producing cells. FS cells are immunocytochemically positive for S-100 protein and GFAP.FS cells contain any secretary granules in their cytoplasm and appear quite different from the hormone-secreting cells. Previous studies have suggested that FS cells play a supportive role for the neighboring glandular cells. For the study of the function in anterior pituitary gland we established novel FS cell line (TtT/GF) from pituitary tumor. We studied about FS cell function and structure using TtT/GF and the FS cells in the anterior pituitary gland in castrated or aging animal. Result obtained as follows. 1) When both TtT/GF cells and growth hormone secreting pituitary tumor cell line (MtT/S) are implanted simultaneously into nude mice produced large growth hormone producing tumor in every animal. In contrast, when nude mice are implanted with MtT/S cell alone, or together with fibroblasts, either no tumors, or very small pituitary tumors were formed. Furthermore, implantation of TtT/GF cells alone produces no tumors.These data indicated the TtT/GF stimulate pituitary tumore formation in nude mice by secreting some growth factor or controlling microenvironment such as by angiogenesis. 2) FS cell produces number of colloid containing follicles in the aging animal. The wet weight of pituitary glands in those animals were 4 times bigger than those of the young animals. Interestingly the prolactin cells specifically appeared around of these follicles which suggests the existing some relationship between prolactin cell proliferation and FS cells in aging animals. 3) The FS cells are increased in number by castration in proportional to LH cell highperplasia which suggesting FS cells also stimulate the proliferation of castration cells in those animals.