INTESTINAL CELL DIFFERENCTIATION IN VIVO AND IN CULTURE

拟议研究的总体目标是研究 体外肠上皮细胞的调节，以及它们表达 微分性质 我们将特别关注以下方面的监管： 通过细胞密度、激素、生长因子、血清 因素 将详细研究糖皮质激素的作用，以确定 这些激素引起生长抑制的机制，并检查 的可能性，惊人的形态变化和新的合成 它们在培养的肠上皮细胞中诱导的蛋白质代表了 肠上皮细胞分化特性的表达 绒毛细胞 细胞-基质相互作用将通过研究 不同类型的胶原蛋白，沉积在培养皿中， 上皮细胞的粘附，纤连蛋白在这方面发挥的作用， 相互作用，以及由上皮细胞合成的胶原类型， 抗坏血酸的存在。 在这些研究过程中，我们将确定增长 速率，DNA合成，细胞周期阶段的持续时间，生长动力学 在存在或不存在各种激素的情况下的抑制和/或刺激 等因素 将进行形态学和超微结构研究 通过透射和扫描电子显微镜。 胶原蛋白的合成将是 通过放射性脯氨酸内部标记和分析， 用已建立的生物化学技术标记蛋白质。

The overall objective of the proposed research is the study of the growth regulation of intestinal epithelial cells in vitro, and their expression of differential properties. We will focus, in particular, on the regulation of proliferation of these cells by cell density, hormones, growth factors, serum factors. The effect of glucocorticoids will be studied in detail to determine the mechanism of the growth inhibition caused by these hormones, and to examine the possibility that the striking morphological changes and the synthesis of new proteins they induce in the cultural intestinal epithelial cells represent the expression of differentiated cell properties characteristics of intestinal villus cells. Cell-substrate interactions will be investigated by studying the effect of different collagen types, desposited in the cultured dishes, on the adhesion of the epithelial cells, the role played by fibronectin in this interaction, and the collagen type(s) synthesized by the epithelial cells in the presence of ascorbate. In the course of these studies, we will determine growth rates, DNA synthesis, duration of cell cycle phases, kinetics of growth inhibition and/or stimulation in the presence or absence of the various hormones and other factors. Morphological and ultrastructural studies will be performed by transmission and scanning electron microscopy. Collagen synthesis will be studied by internal labeling with radioactive proline and analysis of the labeled proteins with established biochemical techniques.