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Growth and development of differentiated functions in primary culture of normal and pre-malignant hepatocytes of regenerating rat liver

再生大鼠肝脏正常及癌前肝细胞原代培养中分化功能的生长发育

基本信息

批准号：
62570324
负责人：
IKAWA Shiro
金额：
$ 1.02万
依托单位：
Tottori University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

Cell-cell contact is known as an important fator in cell growth and tissue formation. The density of hepatocytes in the liver estimated as about 3 x10^5 cells/cm^2, which is twice that in primary culture. In these conditions, in general, hapatocytes do not grow as they are in the G_o state of the cell cycle and show freely differentiated phenotypes. This paper reports growth and development of differentiated functions in primary culture of normal and pre-malignant hepatocytes of regenerating rat liver with special reference to cell density and cell functions. (1) In hepatocytes cultured at low cell density ( 2 x10^4 cells/cm^2 ), the ratio (T/G) of taurine conjugated bile acids (T) to glycine conjugated bile acids(G) was decreased. Conversely, in hepatocytes cultured at high cell density (1x10^5 cells/cm^2), the ratio was increased. (2) Cholesterol synthesis in cultured hepatocytes was greater at low cell density, whereas triglyceride synthesis was much higher at high cell density. (3) … More Isolated plasma membrane was prepared from rat liver. The ratio of bile acid conjugation with amino acids was markedly enhanced in hepatocytes at low cell density by addition of this plasma membrane. The effect of the plasma membrane was dose-dependent and reached a maximum at the concentration of 300 g of membrane protein per 35 mm dish. (4) Addition of plasma membranes also affected the basal activities of 5'-nucleotidase, alkaline phosphatase and Na^+ , K^+ -ATPase of cells at low cell density. (5) The ability of hepatic plasma membrane to mimic the reciprocal effect of increased cell density on cellular activities was almost lost in Ca^<2+> abd Mg^<2+>-free medium.These results in vitro suggest that various functions of hepatocytes in vivo at the mature state and during development and regeneration are all regulated by cell-cell contact and that many functions are not maintained unless the cells from tissue receive complex regulation from cytosocial environment. Therefore, cell surface modulators involved in the regulations of cell functions by cell density do not possibly induce new expression of dormant genes, but regulate phenotypic genes that have already been switched on during terminal differentiation.It would be interesting to know whether the cell surface modulator is responsible for inhibition of related to growth functions and stimulation of hepatocyte characters. This problem must be examined by further purification and characterization of the cell surface modulator responsible for these activities. Less

细胞间的接触是细胞生长和组织形成的重要因素。肝脏中肝细胞的密度估计约为3 x10^5个细胞/cm ^2，是原代培养的两倍。在这些条件下，通常，肝细胞不生长，因为它们处于细胞周期的G_0状态，并显示自由分化的表型。本文报道了再生大鼠肝的正常和癌前肝细胞的原代培养中分化功能的生长和发育，特别是细胞密度和细胞功能。(1)在以低细胞密度（2 × 10^4个细胞/cm ^2）培养的肝细胞中，牛磺酸结合胆汁酸（T）与甘氨酸结合胆汁酸（G）的比值（T/G）降低。相反，在高细胞密度（1 × 10^5个细胞/cm ^2）培养的肝细胞中，该比率增加。(2)胆固醇合成在培养的肝细胞在低细胞密度下更大，而甘油三酯合成在高细胞密度下高得多。（三） ...更多信息从大鼠肝脏制备分离质膜。在低细胞密度的肝细胞中，通过加入这种质膜，胆汁酸与氨基酸结合的比率显著增强。质膜的作用是剂量依赖性的，并在每35 mm培养皿300 g膜蛋白的浓度下达到最大值。(4)质膜的添加也影响了低密度下细胞的5 '-核苷酸酶、碱性磷酸酶和Na^+，K^+ -ATP酶的基础活性。(5)在无Ca^2+和Mg^2+的培养液中，肝细胞质膜几乎丧失了模拟细胞密度增加对细胞活性的相互作用的能力，这些结果表明，在体内肝细胞在成熟状态和发育、再生过程中的各种功能均受细胞的调节。细胞接触，并且除非来自组织的细胞接受来自细胞社会环境的复杂调节，否则许多功能不能维持。因此，参与细胞密度调节细胞功能的细胞表面调节剂不可能诱导休眠基因的新表达，而是调节在终末分化过程中已经开启的表型基因，了解细胞表面调节剂是否负责抑制与生长相关的功能和刺激肝细胞特性将是有趣的。这个问题必须通过进一步纯化和表征负责这些活动的细胞表面调节剂来研究。少