Oestrogen receptor beta-immunoreactive neurones in the ovine hypothalamus: distribution and colocalisation with gonadotropin-releasing hormone.
Oestrogen receptor beta-immunoreactive neurones in the ovine hypothalamus: distribution and colocalisation with gonadotropin-releasing hormone.
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绵羊下丘脑中雌激素受体β免疫反应性神经元：分布及其与促性腺激素释放激素的共定位。
DOI：
10.1111/j.1365-2826.2005.01271.x
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Dufourny,L
中科院分区：
文献类型：
--
作者：
Skinner,DC;Dufourny,L
雌激素对包括绵羊在内的所有被研究物种的大脑促性腺激素释放激素（GnRH）的分泌都有强有力的影响。直到最近，人们假设这种调节是间接发生的，因为很少或没有发现GnRH神经元表达雌激素受体(ER) α。第二种雌激素受体ERβ的发现，以及它随后在大鼠的许多GnRH神经元中的定位，导致了对这一假设的重新考虑。然而，免疫反应性ERβ蛋白在GnRH神经元中的共定位仅在大鼠中得到证实，这提高了雌激素对GnRH神经元的直接调节可能是这种物种特有的可能性。我们之前已经表明，绵羊大脑中的类固醇受体对固定非常敏感，免疫反应细胞的全部补体只有在抗原回收后才能被观察到。因此，本研究的目的是通过免疫细胞化学绘制ERβ神经元在母羊大脑中的分布，并确定表达ERβ的GnRH神经元的比例。采用高温抗原提取和免疫细胞化学方法对4只母羊进行脑切片（20µm）。大量的ERβ免疫反应细胞遍布下丘脑，通过双标记免疫细胞化学，发现超过50%的GnRH神经元表达ERβ免疫反应。这些表达ERβ‐的GnRH神经元在绵羊脑中的功能意义仍有待确定。
Oestrogen powerfully affects the secretion of gonadotropin‐releasing hormone (GnRH) from the brain in all species investigated, including sheep. Until recently, it was hypothesised that such regulation occurs indirectly because few or no GnRH neurones were found to express oestrogen receptor (ER) α. The discovery of a second oestrogen receptor, ERβ, and its subsequent localisation in numerous GnRH neurones in the rat, led to a reconsideration of this hypothesis. However, colocalisation of immunoreactive ERβ protein in GnRH neurones has only been demonstrated in the rat, raising the possibility that such putative direct regulation of GnRH neurones by oestrogen may be peculiar to this species. We have previously shown that steroid receptors in the sheep brain are acutely sensitive to fixation and the full complement of immunoreactive cells can only be visualised after antigen retrieval. The aims of this study were therefore to map immunocytochemically the distribution of ERβ neurones in the ewe brain, and to determine which proportion of GnRH neurones express ERβ. Brain sections (20 µm) from four ewes killed in anestrus were subjected to high temperature antigen retrieval and immunocytochemistry. Numerous ERβ‐immunoreactive cells were located throughout the hypothalamus and, following dual‐label immunocytochemistry, over 50% of the GnRH neurones were found to express immunoreactive ERβ. The functional significance of these ERβ‐expressing GnRH neurones in the ovine brain remains to be determined.