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Study on the development of pituitary adenoma in human GRF-transgenic spontaneous dwarf rats.

人GRF转基因自发性侏儒大鼠垂体腺瘤发生的研究。

基本信息

批准号：
07671146
负责人：
KATAKAMI Hideki
金额：
$ 1.47万
依托单位：
MIYAZAKI MEDICAL COLLEGE
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07671146/
关键词：
spontenous dwarf rat (dr)GHRH-transgenic dwarf rat GH-independent GHRH action pituitary adenoma autocrine mechanism for GHRH-producing pituitary adenoma parathyroid hormone related protein (PTHrP)GRF adenoma発生のautocrine機構 GRF-トランジェニックラット /

项目摘要

Two strains of human growth hormone (GH)-releasing hormone (hGHRH) transgenic rats (2#and#3) were first established by microinjection of a 2.2 kbp-gene constract which consisted of mouse metallothionein I-promoter and human GHRH minigene (exon 1, intron 1, and fusion gene of exon 2-5) into male pronucleus of the oocytes from SD female rats by the standard method. HGHRH-Tg SD male rats were, next, mated with female dwarf rats (dr+/+). Two strains of hGHRH-Tg dr (+/+) were finally obtained by crossing male hGHRH-Tg dwarf rats (+/-) with female dr (+/+). One strain of hGHRH-Tg dr (#2) were analyzed for expression of pituitary hormones, GHRH receptor and c-fos. All hGHRH-Tg dr with high plasma hGHRH levels (>5,000 pg/ml) showed dwarf, but had pituitary adenomas which showed positive immunostaining for hGHRH with some staining for PRL and little staining for ACTH.They showed no immunostaing for GH,TSH-beta, LH-beta or FSH-beta. In contrast to decreased GH gene expression (1/20 of controls), mRNA for rat GHRH receptor and c-fos were markedly increased by 10 and 4 folds, respectively. Expression of hGRF gene was found in the pituitary, liver, spleen, kidney and ovary, while GRF Rc gene transcripts and adenoma formation were exclusively found in the pituitary by northern blot analysis and HE staining, respectively. These results suggest that 1) GH-independent adenoma formation can occur and 2) GRF could act on its Rc and stimulate adenoma formation of the somatotroph by the autocrine mechanism.Although the numer of hGHRH-Tg dr was small due to GH deficiency and not enough to allow extensive survey for gene expression for cytokines, there was an increase in PTHrP gene expresion in adenomatous pituitary glands.

采用常规方法，将由小鼠金属硫蛋白I启动子和人生长激素释放激素（GH）小基因（外显子1、内含子1和外显子2-5的融合基因）组成的2.2kbp的基因连接体注射到SD雌性大鼠卵母细胞的雄性原核内，建立了两株人GH释放激素（hGHRH）转基因大鼠（2#和3#）。然后，将HGHRH-Tg SD雄性大鼠与雌性侏儒大鼠（dr+/+）交配。将雄性hGHRH-Tg侏儒大鼠（+/-）与雌性dr（+/+）杂交，最终获得两株hGHRH-Tg dr（+/+）。分析一株hGHRH-Tg dr（#2）的垂体激素、GHRH受体和c-fos的表达。所有hGHRH-Tg dr血浆hGHRH水平高（> 5，000 pg/ml）的患者均表现为侏儒，但有垂体腺瘤，hGHRH免疫染色阳性，PRL免疫染色阳性，ACTH免疫染色阴性，GH、TSH-β、LH-β和FSH-β免疫染色阴性。与GH基因表达下降（1/20的对照）相比，大鼠GHRH受体和c-fos的mRNA分别显著增加10倍和4倍。hGRF基因在垂体、肝脏、脾脏、肾脏和卵巢中表达，而GRF Rc基因转录本和腺瘤形成仅在垂体中通过北方印迹分析和HE染色发现。结果提示：（1）垂体腺瘤可形成GH非依赖性腺瘤;（2）GRF可作用于Rc，通过自分泌机制刺激生长激素细胞的腺瘤形成，虽然GH缺乏导致hGHRH-Tg dr的数量较少，不足以进行细胞因子基因表达的广泛研究，但垂体腺瘤中PTHrP基因表达增加。