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Effect of nutrition on the gene expression of insulin like growth factor-II Insulin like growth factor-II as an paracrine factor

营养对胰岛素样生长因子-II 基因表达的影响胰岛素样生长因子-II 作为旁分泌因子

基本信息

批准号：
10660269
负责人：
MATSUI Tohru
金额：
$ 1.86万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10660269/
关键词：
Sheep Fattening cattle IGF-I IGF-II Liver Growth plate Protein nutrition Ovariectomy mRNA ウシ IGF-I IGF-II タンパク質欠乏遺伝子発現

项目摘要

Male castrated lambs were given control or a low protein diet. After serum concentration of urea nitrogen became less than normal range in sheep given the low protein diet, a part of liver and growth plate cartilage of the lib were collected. Total RNA was extracted from these tissues. In the first experiment, mRNAs of insulin like growth factors (IGF-I and II) were determined by reverse transcription PCR. Although the mRNA of IGF-I was decreased by protein deficiency in the liver, dietary treatment did not affect the mRNA of IGF-I in the cartilage. Although the mRNA of IGF-II was decreased by protein deficiency in the liver, dietary treatment did not affect the mRNA of IGF-II in the cartilage. These results suggested that the expression of IGFs as endocrine factors (in the liver) was suppressed by protein deficiency but the expression of IGFs as paracrine factors in the catilage was not affected by nutritional stress induced by protein deficiency. There are some transcripts of each IGF because these genes possess several transcription initiation sites. In the second experiment, the transcripts of each IGF gene were determined by reverse transcription PCR. Protein deficiency did not induce consistent tendency of changes in the transcripts of IGF-I or IGF-II in the both tissues, which suggests that the production of these transcripts was differently regulated. And the transcript affected by protein deficiency was not clear in the liver. In the third experiment, we studied the effect of ovariectomy on plasma IGFs concentrations in fattening cattle. Ovariectomy did not affect plasma IGFs concentrations. Plasma IGF-I level was decreased during fattening. There was a positive correlation between plasma IGF-I level and body weight gain during the experiment. On the other hand, plasma IGF-II concentrations were not changed. These results suggest that IGF-I is important endocrine factor on body weight gain in fattening cattle but the effect of IGF-II is not clear.

雄性去势羔羊给予对照或低蛋白饮食。在低蛋白日粮绵羊血清尿素氮浓度低于正常范围后，取部分肝脏和肋生长板软骨。从这些组织中提取总RNA。在第一个实验中，胰岛素样生长因子（IGF-I和II）的mRNA通过逆转录PCR测定。虽然IGF-I的mRNA在肝脏中的蛋白质缺乏减少，饮食治疗并没有影响IGF-I的mRNA在软骨。虽然IGF-II的mRNA在肝脏中的蛋白质缺乏减少，饮食治疗并没有影响软骨中的IGF-II的mRNA。这些结果表明，胰岛素样生长因子的表达作为内分泌因子（在肝脏）蛋白质缺乏抑制，但胰岛素样生长因子的表达作为旁分泌因子的钙蛋白质缺乏引起的营养应激不受影响。每个IGF都有一些转录本，因为这些基因具有几个转录起始位点。在第二个实验中，每个IGF基因的转录本通过逆转录PCR测定。蛋白质缺乏并没有引起一致的趋势，在这两种组织中的IGF-I或IGF-II的转录本的变化，这表明这些转录本的生产是不同的调节。肝脏中蛋白质缺乏对转录的影响并不明显。试验三研究了去卵巢对育肥牛血浆IGFs浓度的影响。卵巢切除术不影响血浆IGFs浓度。血浆IGF-I水平在育肥过程中呈下降趋势。实验期间血浆IGF-I水平与体重增长呈正相关。另一方面，血浆IGF-II浓度未发生变化。这些结果表明，IGF-I是育肥牛增重的重要内分泌因子，而IGF-II的作用尚不清楚。