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STUDIES ON GROWTH SIGNALS DERIVED FROM PROTEIN NUTRITION

蛋白质营养产生的生长信号的研究

基本信息

批准号：
05660147
负责人：
KANAMOTO Ryuhei
金额：
$ 1.41万
依托单位：
Kyoto Prefectural University (1994)Jikei University School of Medicine (1993)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

Recent knowledge of molecular biology indicates that cell growth and proliferation are required growth signals and its signal transduction. Although growth of young animals is related to nutritional status, the interaction between nutrition and growth-related signal transduction has not been studied thoroughly. The aim of our study is to determine whether protein nutrition affects signal transduction for cell growth in the tissues of growing animals depending on its nutritional quality. For this purpose, we examined expression of several growth-related genes and DNA synthesis in tissues of growing rats under a variety of nutritional conditions. The results obtained under this project are ; (1) The levels of c-myc and insulin-like growth factor-1 (IGF-1) mRNA in the liver of growing rats varied in a reciprocal manner in response to changes in either quantity or quality of diet. In contrast to many previous works the c-myc mRNA increased in the liver of malnourished rats in which growth was arrested. (2) Feeding of casein diet to the rats maintained on protein-free diet caused rapid decrease in the level of c-myc mRNA and induced the DNA synthesis in the liver. The level of IGF-1 mRNA increased rapidly under this condition. (3) Zein diet, which lacks tryptophan and lysine, did not change the c-myc and the IGF-1 mRNA levels nor induced DNA synthesis in the liver unless it was supplemented with tryptophan and lysine. (4) The level of c-myc mRNA increased rapidly more than 18-fold when amino acids were removed from the medium indicating that the expression of c-myc was regulated directory by nutritional environment.In conclusion, lemphasize the possibility that nutrition not only supplies material for body components but also affects the signal transduction for cell growth in young growing rats.

最近的分子生物学知识表明，细胞的生长和增殖是生长信号及其信号转导所必需的。尽管幼年动物的生长与营养状况有关，但营养与生长相关信号转导之间的相互作用尚未得到深入研究。我们研究的目的是确定蛋白质营养是否影响生长中动物组织中细胞生长的信号转导，这取决于其营养质量。为此，我们检测了在不同营养条件下生长大鼠组织中几个生长相关基因的表达和DNA合成。研究结果如下：(1)生长大鼠肝脏c-myc和胰岛素样生长因子-1(IGF-1)的mRNA水平随饮食的数量和质量的变化而变化。与许多以前的工作不同，c-myc基因在生长受阻的营养不良大鼠的肝脏中增加。(2)饲喂酪蛋白饲料可引起大鼠肝脏c-myc基因表达水平迅速下降，并诱导肝组织DNA合成。在此条件下，IGF-1mRNA水平迅速升高。(3)缺乏色氨酸和赖氨酸的玉米醇溶蛋白饲料，不添加色氨酸和赖氨酸，不改变肝脏c-myc和IGF-1的基因表达水平，也不能诱导肝脏DNA合成。(4)去除培养液中的氨基酸后，c-myc基因的表达水平迅速增加了18倍以上，表明c-myc的表达受营养环境的调控。