Comparative analysis of the pituitary and ovarian GnRH systems in the leopard gecko: signaling crosstalk between multiple receptor subtypes in ovarian follicles
Comparative analysis of the pituitary and ovarian GnRH systems in the leopard gecko: signaling crosstalk between multiple receptor subtypes in ovarian follicles
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DOI：
10.1677/jme-06-0010
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发表时间：
2007-02-01
影响因子：
3.5
通讯作者：
Park, Min Kyun
中科院分区：
文献类型：
--
作者：
Ikemoto, Tadahiro;Park, Min Kyun
在脊椎动物中，GnRH通过与其脑下垂体受体相互作用来调节生殖功能。目前的研究表明，豹壁虎分别具有GnRH配体和受体的两个和三个基因，尽管长期以来人们认为爬行动物中不存在三个受体亚型之一。每种受体亚型都表现出不同的药理作用。所有类型的配体和受体都表现出不同的表达模式，在大脑内外都有广泛的表达。这份报告还显示了产卵季节期间和产卵后豹壁虎的垂体和卵巢促性腺激素释放激素系统的比较。三种受体亚型在整个脑垂体和卵巢中均有表达，但在脑下垂体前叶中只有一种受体亚型表达。原位杂交显示了卵巢受体的空间表达模式，提示多种受体亚型在较大卵泡的颗粒细胞中共表达。与单独转染组相比，受体亚型联合转染组在COS-7细胞中表现出不同的药理作用。这些结果表明，不同的信号机制参与了垂体和卵巢的GnRH系统。垂体前叶和卵泡中受体表达的季节性和发育性变化可能有助于这种动物的季节性繁殖。
GnRH regulates reproductive functions through interaction with its pituitary receptor in vertebrates. The present study demonstrated that the leopard gecko possessed two and three genes for GnRH ligands and receptors, respectively, though one of the three receptor subtypes had long been thought not to exist in reptiles. Each receptor subtype showed a distinct pharmacology. All types of ligands and receptors showed different expression patterns, and were widely expressed both inside and outside the brain. This report also shows a comparison of the pituitary and ovarian GnRH systems in the leopard gecko during and after the egg-laying season. All three receptor subtypes were expressed in both the whole pituitary and ovary; however, only one receptor subtype could be detected in the anterior pituitary gland. In situ hybridization showed spatial expression patterns of ovarian receptors, and suggested co-expression of multiple receptor subtypes in granulosa cells of larger follicles. Co-transfection of receptor subtypes showed a distinct pharmacology in COS-7 cells compared with those of single transfections. These results suggest that distinct signaling mechanisms are involved in the pituitary and ovarian GnRH systems. Seasonal and developmental variations in receptor expression in the anterior pituitary gland and ovarian follicles may contribute to the seasonal breeding of this animal.