Expression of estradiol receptor, GPR30, in bovine anterior pituitary and effects of GPR30 agonist on GnRH-induced LH secretion
Expression of estradiol receptor, GPR30, in bovine anterior pituitary and effects of GPR30 agonist on GnRH-induced LH secretion
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DOI：
10.1016/j.anireprosci.2013.04.003
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发表时间：
2013-06-01
影响因子：
2.2
通讯作者：
Kadokawa, Hiroya
中科院分区：
文献类型：
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作者：
Rudolf, Faidiban O.;Kadokawa, Hiroya
G蛋白偶联受体30（GPR 30）是位于质膜上的雌二醇受体，它启动几个快速的非基因组信号传导事件。最近在大鼠垂体前叶（AP）中发现了GPR 30，然而，对GPR 30在动物促性腺激素分泌中的作用知之甚少。为了填补这一研究空白，我们假设GPR 30在牛AP中表达，并介导雌二醇抑制促性腺激素释放激素（GnRH）诱导的LH释放。通过RT-PCR、免疫印迹和免疫组化检测GPR 30 mRNA和蛋白的表达。我们在无类固醇条件下培养牛AP细胞（n = 8）3天，然后在GnRH刺激前用浓度递增（0.001 nM、0.01 nM、0.1 nM、1 nM和10 nM）的雌二醇或GPR 30特异性激动剂G1处理5分钟。正如预期的那样，0.001-0.1 nM雌二醇抑制GnRH刺激的LH分泌。然而，我们还发现0.001 nM的G1能够抑制这种分泌（P < 0.05）。相反，雌二醇和G1在较高剂量下抑制GnRH刺激的LH分泌的效率较低。雌二醇和G1均不抑制GnRH刺激的促卵泡激素分泌。在单独的实验中，荧光免疫组织化学和免疫细胞化学显示，约50%的GPR 30阳性细胞表达LH，约30%的LH阳性细胞表达GPR 30。总之，GPR 30在牛促性腺激素细胞和其他AP细胞中表达，并可能部分促进GnRH诱导的LH分泌的快速负雌二醇反馈。(c)2013爱思唯尔有限公司版权所有。
G-protein - coupled receptor 30 (GPR30) is an estradiol receptor located on the plasma membrane, and it initiates several rapid, non-genomic signaling events. GPR30 has recently been identified in rat anterior pituitary (AP); however, little is known about the role of GPR30 in controlling luteinizing hormone (LH) secretion from gonadotropes in animals. To fill this research gap, we hypothesized that GPR30 is expressed in bovine AP and mediates estradiol inhibition of gonadotropin-releasing hormone (GnRH)-induced LH release. We confirmed the expressions of GPR30 mRNA and protein by RT-PCR, western blotting, and immunohistochemistry. We cultured bovine AP cells (n = 8) for 3 days in steroid-free conditions and then treated them with increasing concentrations (0.001 nM, 0.01 nM, 0.1 nM, 1 nM, and 10 nM) of estradiol or a GPR30-specific agonist, G1, for 5 min before GnRH stimulation. As expected, estradiol at 0.001-0.1 nM inhibited the GnRH-stimulated LH secretion. However, we found also that G1 at 0.001 nM was able to inhibit this secretion (P < 0.05). In contrast, both estradiol and G1 at higher doses were less efficient in suppressing the GnRH-stimulated LH secretion. Neither estradiol nor G1 suppressed GnRH-stimulated follicle-stimulating hormone secretion. In separate experiments, fluorescent immunohistochemistry and immunocytochemistry revealed that approximately 50% of GPR30-positive cells express LH, and about 30% of LH-positive cells express GPR30. In conclusion, GPR30 is expressed in bovine gonadotropes and other AP cells and may partially contribute to rapid negative estradiol feedback of GnRH-induced LH secretion. (c) 2013 Elsevier B.V. All rights reserved.