Study for phathophysiology of precocious puberty

性早熟的病理生理学研究

基本信息

批准号：
07557365
负责人：
MINEGISHI Takashi
金额：
$ 1.41万
依托单位：
Gunma University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
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-07557365/
关键词：
FSH receptor precocious puberty desensitization COS細胞

项目摘要

We have examined the DNA sequences of FSH receptor cording region from the patients of precocious puberty, and we have found a point mutation in these samples. Currently we try to see the functional significance of this mutation using receptor cDNA transfected cells.Because it is well documented that the FSH receptor is internalized as a consequence of hormone binding, we examine the ability of cells expressing FSH receptor to mediate ^<125>I-FSH internalization. In this experimental approach, the cells were incubated at 37 C in the continuous presence of ^<125>I-FSH and at various times were assayd for surface-bound and internalized ^<125>I-FSH.The results indicated that a fast down-regulation of cell surface FSH receptor and a 50% loss of cell surface receptors occurred after 4 h incubation. It will be important to identify which parameters determine the rate of internalization of the hormone-occupied receptor in different cells. Since the preincubation with forskolin or FSH causes a decrease in the cAMP response to FSH,the preincubation conditions result in desensitization of the gonadotropin-responsive adenylyl cyclase. Therefore these results reveal evidence of desensitization occurring in the absence of receptor down-regulation, suggesting that uncoupling of the FSH receptor is also present in this cell types. Uncoupling of the receptor may be defined as a process by which the functional activity of the receptor is decreased despite a maintained receptor number, whereas down-regulation implies a reduction in the number of available receptors.

我们已经检查了早熟青春期患者的FSH受体绳索区域的DNA序列，并且在这些样品中发现了一个点突变。目前，我们试图使用受体cDNA转染的细胞看到该突变的功能意义。因为有充分的文献证明，由于激素结合，FSH受体被内在化，我们检查了表达FSH受体介导 ^<125> i-fsh内在化的细胞的能力。在这种实验方法中，在连续存在 ^<125> i-FSH的情况下将细胞在37 C下孵育，并在不同时间进行表面结合和内在化的 ^<125> I-FSH孵育。结果表明，在4 h启动后，细胞表面FSH受体的快速下调，细胞表面受体的损失发生了50％。确定哪些参数确定不同细胞中激素占领受体的内在化速率将很重要。由于与Forskolin或FSH进行预孵育会导致cAMP对FSH的反应减少，因此预孵育条件会导致促性腺激素反应性腺苷酸糖环酶脱敏。因此，这些结果揭示了在没有受体下调的情况下发生脱敏的证据，表明该细胞类型中也存在FSH受体的解偶。受体的解耦合可以定义为尽管受体数量保持受体数量，但受体的功能活性会降低，而下调意味着可用受体数量减少。