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Differential production and regulation of two gonadotropins (GTH I and GTH II) in teleost pituitary gonadotrophs during reproductive development.

生殖发育过程中硬骨鱼垂体促性腺激素中两种促性腺激素（GTH I 和 GTH II）的差异产生和调节。

基本信息

批准号：
63570015
负责人：
NAITO Nobuko
金额：
$ 1.34万
依托单位：
Showa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

Two chemically distinct gonadotropins (GTH I and GTH II) have been purified from chum salmon pituitary. Chemical and biological characterizations have revealed that GTH II is the gonadotropin concerning gonadal maturation and ovulation, however, GTH I is a new hormone and its physiological function still remains unknown. Immunocytochemistry, Lising specific antisera to beta-subunit of GTH I and GTH II, have suggested that two distinct gonadotropins (GTH I and GTH II) are synthesized mainly in two distinct gonadotrophs in salmoned pituitary. In addition, GTH I content in blood plasma is relatively high in vitellogenic phase as compared with in ovulating phase in salmoneds.This study examined differential production and regulation of gonadotropins sub-units in rainbow trout (*) pituitary gonadotrophs during reproductive development, using cDNA probes of their alpha - and beta-subunits by in situ hybridization histochemistry. (1) The mRNA of alpha -subunit of GTH I and GTH II were detected prior to any signals of beta- subunits of GTH I or GTH II in immature rainbow trouts. (2) The mRNA of beta-subunit of GTH I were observed in the early phase of vitellogenic phase, always prior to that of GTH II, and increased during vitellogenic phase and then declined before maturation. (3) The mRNA of beta-subunit of GTH II began to increase extremely during post vitellogenic and maturating phases of gonadal development. These results suggest that GTH I-synthesis occurs from early vitellogenic phase prior to that of GTH II, and may play functional role during vitellogenesis in the ovary. However, functional relationship between GTH I and GTH II, just like FSH and LH in mammalian pituitary, still remains unsolved.

两种化学性质不同的促性腺激素（GTH I和GTH II）已从鲑鱼脑垂体中纯化。化学和生物学特性表明，GTH Ⅱ是与性腺成熟和排卵有关的促性腺激素，而GTH Ⅰ是一种新的激素，其生理功能尚不清楚。免疫细胞化学显示，鲑鱼垂体中两种不同的促性腺激素（GTH I和GTH II）主要由两种不同的促性腺激素细胞合成。本研究以虹鳟（*）垂体促性腺激素细胞的α-和β-亚基cDNA为探针，采用原位杂交组织化学方法，研究了虹鳟（*）垂体促性腺激素细胞在生殖发育过程中促性腺激素亚基的差异产生和调节。(1)未成熟虹鳟鱼中GTH Ⅰ和GTH Ⅱ α亚基的mRNA先于GTH Ⅰ和GTH Ⅱ β亚基的信号被检测到。(2)GTH Ⅰ β亚基的mRNA在卵黄发生早期就有表达，始终先于GTH Ⅱ，在卵黄发生期表达增加，成熟前表达下降。(3)GTH Ⅱ β亚基的mRNA在卵黄发生后期和性腺发育成熟期开始显著增加。这些结果表明，GTH I的合成发生在卵黄发生的早期，先于GTH II的合成，并可能在卵巢卵黄发生过程中发挥功能作用。然而，GTH I和GTH II之间的功能关系，就像哺乳动物垂体中的FSH和LH一样，仍然没有得到解决。