Expression of thyrotropin-releasing hormone receptors in rat testis and their role in isolated Leydig cells
Expression of thyrotropin-releasing hormone receptors in rat testis and their role in isolated Leydig cells
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DOI：
10.1007/s00441-008-0680-y
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发表时间：
2008-09
影响因子：
3.6
通讯作者：
Yong Zhao;W. Hou;Hua-ping Zhu;Jie Zhao;Rui‐an Wang;Ruojun Xu;Yuan-qiang Zhang
中科院分区：
文献类型：
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作者：
Yong Zhao;W. Hou;Hua-ping Zhu;Jie Zhao;Rui‐an Wang;Ruojun Xu;Yuan-qiang Zhang
促甲状腺激素释放激素（TRH）最初被发现是一种在下丘脑合成的神经肽。该激素的受体包括 TRH 受体 1 (TRH-R1) 和 -2 (TRH-R2)。先前的研究表明，TRH-R1 和 TRH-R2 只存在于成体 Leydig 细胞 (ALC) 中。我们通过使用蛋白质印迹、免疫组织化学和免疫荧光研究了出生后 8、14、21、35、60 和 90 日龄大鼠以及乙二甲磺酸 (EDS) 处理的成年大鼠睾丸中 TRH-R1 和 TRH-R2 的表达。还检查了 TRH 对 90 日龄大鼠原代培养 ALC 睾酮分泌和 21 日龄大鼠 Leydig 细胞 DNA 合成的影响。蛋白质印迹和免疫组织化学表明，TRH-R1 和 TRH-R2 在胎儿 Leydig 细胞（8 日龄大鼠）以及发育过程中所有阶段的成年型 Leydig 细胞中表达。免疫荧光双重染色显示，EDS 21 天后的大鼠中新再生的 Leydig 细胞在首次再现时表达 TRH-R1 和 TRH-R2。与不同剂量的 TRH 一起孵育会影响原代培养的 ALC 的睾酮分泌。低浓度的 TRH（0.001、0.01 和 0.1 ng/ml）抑制分离 ALC 的基础和人绒毛膜促性腺激素 (hCG) 刺激的睾酮分泌，而相对高剂量的 TRH（1 和 10 ng/ml）则增加 hCG 刺激的睾酮分泌。 5-溴-2'-脱氧尿苷掺入试验检测到，低 TRH 浓度促进了 21 日龄大鼠 Leydig 细胞的 DNA 合成。由此，我们阐明了TRH对睾丸功能的影响：TRH可能调节成熟前睾丸间质细胞的发育和成熟后睾酮的分泌。
Thyrotropin-releasing hormone (TRH) was initially discovered as a neuropeptide synthesized in the hypothalamus. Receptors for this hormone include TRH-receptor-1 (TRH-R1) and -2 (TRH-R2). Previous studies have shown that TRH-R1 and TRH-R2 are localized exclusively in adult Leydig cells (ALCs). We have investigated TRH-R1 and TRH-R2 expression in the testes of postnatal 8-, 14-, 21- 35-, 60-, and 90-day-old rats and in ethane dimethane sulfonate (EDS)-treated adult rats by using Western blotting, immunohistochemistry, and immunofluorescence. The effects of TRH on testosterone secretion of primary cultured ALCs from 90-day-old rats and DNA synthesis in Leydig cells from 21-day-old rats have also been examined. Western blotting and immunohistochemistry demonstrated that TRH-R1 and TRH-R2 were expressed in fetal Leydig cells (in 8-day-old rats) and in all stages of adult-type Leydig cells during development. Immunofluorescence double-staining revealed that newly regenerated Leydig cells in post-EDS 21-day rats expressed TRH-R1 and TRH-R2 on their first reappearance. Incubation with various doses of TRH affected testosterone secretion of primary cultured ALCs. Low concentrations of TRH (0.001, 0.01, and 0.1 ng/ml) inhibited basal and human chorionic gonadotrophin (hCG)-stimulated testosterone secretion of isolated ALCs, whereas relatively high doses of TRH (1 and 10 ng/ml) increased hCG-stimulated testosterone secretion. As detected by a 5-bromo-2′-deoxyuridine incorporation test, the DNA synthesis of Leydig cells from 21-day-old rats was promoted by low TRH concentrations. Thus, we have clarified the effect of TRH on testicular function: TRH might regulate the development of Leydig cells before maturation and the secretion of testosterone after maturation.