Dynamic regulation of pituitary mRNAs for bone morphogenetic protein (BMP) 4, BMP receptors, and activin/inhibin subunits in the ewe during the estrous cycle and in cultured pituitary cells
Dynamic regulation of pituitary mRNAs for bone morphogenetic protein (BMP) 4, BMP receptors, and activin/inhibin subunits in the ewe during the estrous cycle and in cultured pituitary cells
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DOI：
10.1677/joe-10-0035
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发表时间：
2010-10-01
影响因子：
4
通讯作者：
Taragnat, C.
中科院分区：
文献类型：
--
作者：
Sallon, C.;Faure, M. O.;Taragnat, C.
最近，骨形态发生蛋白（BMP）4已被证明抑制FSH分泌母羊。垂体中BMP 4 mRNA和BMP受体的检测表明，BMP 4对FSH的产生具有旁分泌作用。本工作旨在确定在发情周期中，当FSH β mRNA和FSH释放发生变化时，BMP 4和/或BMP受体mRNA以及激活素/β-受体亚基mRNA是否发生波动。母羊的发情周期与孕激素海绵同步。在卵泡晚期（n=5）、第二次FSH高峰前（n=4）和黄体期（n=4）处死母羊。使用定量逆转录-PCR，我们发现，BMP 4，BMP受体，分化抑制剂2（Id 2），BMP 4的靶基因和头蛋白的mRNA水平在整个发情周期中没有显着变化。与此相反，激活素β B mRNA水平和激活素β B亚单位免疫反应阳性细胞的百分比在FSH第二次激增之前高于其他组。在母羊垂体细胞培养物中，激活素、GnRH或雌二醇-17 β（E-2）对BMP 4、BMP受体和Id 2 mRNA的水平没有显著影响。E-2，而不是GnRH，增加激活素β B mRNA的水平。此外，在体外FSH的释放没有修改的头蛋白，BMP拮抗剂。相反，激活素途径抑制剂SB 431542抑制FSH释放。总的来说，我们的数据表明，垂体BMP 4不会在调节FSH的产生在发情周期中发挥关键作用，而局部激活素B将是一个主要的刺激FSH合成所必需的二次FSH激增。内分泌学杂志（2010）207，55-65
Recently, bone morphogenetic protein (BMP) 4 has been shown to inhibit FSH secretion in ewe. The detection of BMP4 mRNA and BMP receptors in the pituitary suggests that BMP4 can exert paracrine actions on FSH production. This work aimed at determining whether BMP4 and/or BMP receptor mRNA as well as activin/inhibin subunit mRNA fluctuates during the estrous cycle when FSH beta mRNA and FSH release changed. The estrous cycles of ewes were synchronized with progestagen sponges. Ewes were killed in late follicular stage (n=5), before the secondary FSH surge (n=4), and in luteal phase (n=4). Using quantitative reverse transcription-PCR, we showed that the levels of mRNA for BMP4, BMP receptor, the inhibitor of differentiation 2 (Id2), a target gene of BMP4, and noggin did not change significantly across the estrous cycle. In contrast, the level of activin beta B mRNA and the percentage of immunoreactive cells for activin beta B-subunit were higher before the secondary surge of FSH compared to other groups. In ewe pituitary cell cultures, activin, GnRH, or estradiol-17 beta (E-2) did not significantly affect the levels of BMP4, BMP receptor, and Id2 mRNA. E-2, but not GnRH, increased the level of activin beta B mRNA. Moreover, the in vitro FSH release was not modified by noggin, a BMP antagonist. In contrast, SB431542, an inhibitor of activin pathway, inhibited FSH release. Collectively, our data showed that pituitary BMP4 would not play a crucial role in the regulation of FSH production during the estrous cycle, whereas local activin B would be a major stimulus of FSH synthesis necessary for the secondary FSH surge. Journal of Endocrinology (2010) 207, 55-65