Yao Bing, Kawaminami Mitsumori
Laboratory of Veterinary Physiology, Kitasato University, Aomori, Japan.
J Reprod Dev. 2008 Aug;54(4):259-64. doi: 10.1262/jrd.20039. Epub 2008 May 27.
The distribution and regulation of annexin A5 expression, a gonadotropin releasing hormone (GnRH) receptor regulated protein in gonadotropes and luteal cells, in the testes of rats were examined. Immunocytochemical staining revealed high levels of annexin A5 in the Leydig and endothelial cells and lower levels in the primary spermatocytes and sperm. Hemicastration significantly increased the annexin A5 content of the remaining testis within 24 h. Annexin A5 immunoreactivity was increased mainly in interstitial tissues including the peritubular cells, while some spermatocytes also showed higher intensity of annexin A5 in the remaining testis. Administration of hCG (50 IU) enhanced the testicular content of annexin A5 after 24 h. This treatment expanded the area of interstitial tissue in the testis and increased annexin A5 immunoreactivity, but the area of the endothelial cells was unchanged. Similarly, human chorionic gonadotropin (hCG) enhanced annexin A5 expression in a primary culture of testis cells that consisted of mainly interstitial cells. Because GnRH stimulates the expression of annexin A5 in the gonadotropes and luteal cells, we examined the effect of GnRH on annexin A5 expression in the testes. We found that des-Gly10 [Pro9]-GnRH ethylamide (100 nM), a GnRH agonist, increased annexin A5 expression in cultured testis cells and that Cetrorelix (100 nM), a GnRH antagonist, inhibited the effect of hCG on annexin A5 expression. These results suggest that pituitary luteinizing hormone promotes annexin A5 synthesis in Leydig cells and that this effect could be mediated by local GnRH in the testis.
对大鼠睾丸中膜联蛋白A5（一种在促性腺激素细胞和黄体细胞中受促性腺激素释放激素（GnRH）受体调节的蛋白质）的表达分布及调控进行了研究。免疫细胞化学染色显示，睾丸间质细胞和内皮细胞中膜联蛋白A5水平较高，而初级精母细胞和精子中的水平较低。单侧睾丸切除术后24小时内，剩余睾丸的膜联蛋白A5含量显著增加。膜联蛋白A5免疫反应性主要在包括睾丸周细胞在内的间质组织中增强，而剩余睾丸中的一些精母细胞也显示出更高强度的膜联蛋白A5。注射人绒毛膜促性腺激素（hCG，50 IU）24小时后，睾丸中膜联蛋白A5含量增加。这种处理扩大了睾丸间质组织的面积并增加了膜联蛋白A5免疫反应性，但内皮细胞的面积未改变。同样，人绒毛膜促性腺激素（hCG）增强了主要由间质细胞组成的睾丸细胞原代培养物中膜联蛋白A5的表达。由于GnRH刺激促性腺激素细胞和黄体细胞中膜联蛋白A5的表达，因此我们研究了GnRH对睾丸中膜联蛋白A5表达的影响。我们发现，GnRH激动剂去甘氨酸10 [脯氨酸9] -GnRH乙酰胺（100 nM）增加了培养的睾丸细胞中膜联蛋白A5的表达，而GnRH拮抗剂西曲瑞克（100 nM）抑制了hCG对膜联蛋白A5表达的影响。这些结果表明，垂体促黄体生成素促进睾丸间质细胞中膜联蛋白A5的合成，且这种作用可能由睾丸局部的GnRH介导。
