A Enzyme Cytochemical Study of Intra-Cellular Singnaling System of Anterior Pituitary Hormone Producing Cells.

众所周知，细胞外刺激通过改变细胞内环AMP的浓度而在细胞中产生特异性反应，腺苷酸环化酶是引起环AMP的酶。细胞中的环AMP被环3 '，5'-核苷酸磷酸二酯酶降解为腺苷一磷酸，然后腺苷一磷酸被5 '-核苷酸酶分解为腺苷和正磷酸，并最终导致cAMP代谢级联。虽然这些酶的细胞化学定位已被研究在许多器官，几乎没有报告出现在垂体。本文介绍了Saito和Keino（1975）的腺苷酸环化酶、Takizawa和Saito（1992）的磷酸二酯酶和Wachstein和Meisel（1975）的5 ′-核苷酸酶的电镜酶组织化学方法，以了解这些酶在大鼠垂体前叶的定位。 ...更多信息 在GH细胞的质膜上观察到类蛋白酶活性。在部分卵泡星状细胞（F-S细胞）的微绒毛上观察到强阳性反应产物。磷酸二酯酶活性在PRL细胞的胞质中呈阳性。在一些GH细胞中，在细胞质中观察到微弱的反应产物。除GH细胞外，在某些LH/FSH细胞的质膜上观察到5 '-核苷酸酶反应产物呈阳性。上述结果有趣地提示，垂体前叶细胞在组成细胞的环核苷酸代谢酶中存在特异性差异。除了垂体前叶激素产生细胞，腺苷酸环化酶和鸟苷酸环化酶的超微细胞化学定位进行了研究，在边缘细胞层表面的垂体腔。边缘细胞层的细胞，包括微绒毛和纤毛在内的面向腔的质膜上的腺苷酸环化酶和鸟苷酸环化酶活性较强。观察到类似的鸟苷酸环化酶活性定位。结果提示，边缘细胞层的组成细胞对垂体可能有一定的调节作用。少

It is well understood that extracellular stimuli produce specific responses in the cells by changing the intracellular concentrations of cyclic-AMP and that adenylate cyclase is the enzyme which gives rise to it. Cyclic-AMP in the cell is degraded by cyclic 3',5'-nucleotide phosphodiesterase into adenosine monophosphate, then adenosine monophosphate receives a break-down by 5'-nucleotidase into adenosine and orthophosphate, and terminally results in a cAMP metabolic cascade. Although the cytochemical localization of these enzymes have been studied in many organs, almost no report has appeared on the pituitary gland. The present study aimed at knowing localization of these enzymes in the rat anterior pituitary gland by means of electron microscopic enzyme histochemistry, introducing the following media of Saito and Keino (1975) for adenylate cyclase, Takizawa and Saito (1992) for phosphodiesterase, and Wachstein and Meisel (1975) for 5'-nucleotidase.The reaction product for adenylate cy … More clase activity was observed on the plasma membrane of GH cells. Strongly positive reaction product was observed on the microvilli of some folliculo-stellate cells (F-S cells). The phosphodiesterase activity was demonstrated as positive in the cytoplasm of the PRL cells. In some GH cells, reaction product was weakly observed in the cytoplasm. The reaction products for 5'-nucleotidase were observed positive on the plasma membrane of some of the LH/FSH cells in addition to the GH cells. The above results interestingly suggest that the anterior pituitary cells present specific differences in the cyclic nucleotide metabolizing enzymes in constituent cells. In addition to the anterior pituitary hormone producing cells, ultracytochemical localization of adenylate cyclase and guanylate cyclase was studied in the marginal cell layer surfacing the pituitary cavity. The cells in the marginal cell layer showed strong activity of adenylate cyclase and guanylate cyclase on the plasm membrane facing to the cavity, including micrivilli and cilia. Similar localization of guanylate cyclase activity was observed. The results suggest that the constituent cells of the marginal cell layer may have some regulatory function on the pituitary gland. Less