DIFFERENTIATED FUNCTION IN DISPERSED CELL CULTURES

这项研究计划的总体目标是调查对 在已建立的克隆株中的几种细胞或器官特异性功能 在培养中分化的哺乳动物细胞。研究将集中在 荷尔蒙分泌、荷尔蒙反应的垂体细胞株(GH细胞)。这个 使用的方法包括生化、免疫学、细胞学、 电生理学和基因技术。五个具体目标将是 检查过了。1.生长激素细胞上3种调节肽的质膜受体 促甲状腺激素释放激素，TRH；生长抑素，SRIH：和表皮生长 因子，EGF)将被表征。重点将放在机制上 通过同源和亲和力调节每个受体的浓度和亲和力 异源配体。2.促肾上腺皮质激素释放激素、促性腺激素释放激素、促性腺激素释放激素的急性作用机制 将对生长激素细胞的EGF进行研究。离子通量、蛋白质的作用 催乳素和生长激素的磷酸化和电生理事件 将对释放进行检查。3.糖皮质激素对ACTH释放的急性抑制作用 激素将在ATT 20/D16细胞中进行研究。4.将会决定 同一生长激素细胞是否同时产生生长激素和催乳素 同时。5.肿瘤促进剂(如佛波醇)的作用 双酯)对培养细胞分化功能的影响将用 强调膜的改变。拟议中的实验利用了 肿瘤细胞在培养中的几个独特性质，并允许研究 否则将很难或不可能完成。现有证据 表明在这些肿瘤细胞中阐明的许多机制也 适用于正常细胞。

The broad objective of this research plan is to investigate the control of several cell- or organ-specific functions in established clonal strains of differentiated mammalian cells in culture. Studies will focus on hormone-producing, hormone-responsive pituitary cell strains (GH-cells). The methods to be used include biochemical, immunologic, cytologic, electrophysiologic and genetic techniques. Five specific objectives will be examined. 1. Plasma membrane receptors on GH-cells for 3 regulatory peptides (thyrotropin-releasing hormone, TRH; somatostatin, SRIH: and epidermal growth factor, EGF) will be characterized. Emphasis will be on the mechanisms regulating the concentrations and affinities of each receptor by homologous and heterologous ligands. 2. The mechanisms of the acute actions of TRH, SRIH and EGF on GH-cells will be studied. The roles of ion fluxes, protein phosphorylation, and electrophysiologic events in prolactin and growth hormone release will be examined. 3. Acute inibition of ACTH release by glucocorticoid hormones will be investigated in AtT 20/D16 cells. 4. It will be determined whether the same GH-cell produces both growth hormone and prolactin simultaneously. 5. The actions of tumor promoters (such as the phorbol diesters) on differentiated functions in cultured cells will be examined with an emphasis on membrane alterations. The experiments proposed take advantage of several unique properties of tumor cells in culture and permit studies that would be difficult or impossible to perform otherwise. Available evidence indicates that many of the mechanisms elucidated in these neoplastic cells also apply to normal cells.