Pituitary gonadotropins, follicle-stimulating hormone (Fsh) and luteinizing hormone (Lh), control oogenesis in all vertebrates. In particular, Lh plays a key role in stimulating the final oocyte maturation and subsequent ovulation. The biosynthesis and secretion of Lh are regulated by several neurohormones, including gonadotropin-releasing hormone (GnRH) and dopamine. GnRH analogs, also known as Lh releasing hormone analogs (LHRHa), and dopamine antagonists are commonly used to induce sexual maturation in teleosts. However, the effects of these reagents differ among fish species. Therefore, in the present study, the effects of LHRHa and pimozide (a dopamine antagonist) on Lh release and ovulation induction were investigated in female eels whose ovarian development was artificially induced by recombinant Fsh with ovaries containing oocytes at the migratory nucleus stage in vitro and/or in vivo. Both LHRHa and pimozide stimulated the release of Lh from pituitary cells in a dose-dependent manner in vitro. Furthermore, the synergistic effects of LHRHa and pimozide were observed in the release of Lh from the pituitary gland. In vivo experiments demonstrated that the administration of pimozide alone or in combination with LHRHa induced the release of Lh and the fusion of oil droplets in oocytes. In addition, 17α-hydroxyprogesterone (OHP) combined with LHRHa and pimozide resulted in complete ovulation at a high rate (87.5% complete ovulation and 12.5% partial ovulation), whereas LHRHa and pimozide without OHP induced partial ovulation at a low rate (0% complete ovulation and 14.3% partial ovulation). These results suggest that combined treatment with LHRHa, pimozide, and OHP could induce ovulation in artificially matured female Japanese eels. However, future studies are needed to evaluate the quality of embryos produced by females induced with LHRHa, pimozide and OHP. Additionally, the pituitary gland obtained from female eels with artificially induced sexual maturation is suitable for investigating the mechanisms of Lh release.

垂体促性腺激素、促卵泡激素 （Fsh） 和黄体生成素 （Lh） 控制所有脊椎动物的卵子发生。特别是，Lh 在刺激最终卵母细胞成熟和随后的排卵中起关键作用。Lh 的生物合成和分泌受多种神经激素调节，包括促性腺激素释放激素 （GnRH） 和多巴胺。GnRH 类似物，也称为 Lh 释放激素类似物 （LHRHa） 和多巴胺拮抗剂，通常用于诱导硬骨动物的性成熟。然而，这些试剂的效果因鱼类而异。因此，在本研究中，研究了 LHRHa 和 pimozide（一种多巴胺拮抗剂）对 Lh 释放和排卵诱导的影响，这些雌性鳗鱼的卵巢发育是由重组 Fsh 人工诱导的，卵巢在体外和/或体内处于迁徙核阶段。LHRHa 和 pimozide 在体外以剂量依赖性方式刺激垂体细胞释放 Lh。此外，在垂体释放 Lh 中观察到 LHRHa 和 pimozide 的协同作用。体内实验表明，单独施用 pimozide 或与 LHRHa 联合施用可诱导卵母细胞中 Lh 的释放和油滴的融合。此外，17α-羟孕酮 （OHP） 与 LHRHa 和 pimozide 联合导致高率完全排卵（87.5% 完全排卵和 12.5% 部分排卵），而 LHRHa 和不含 OHP 的 pimozide 以低速率诱导部分排卵（0% 完全排卵和 14.3% 部分排卵）。 这些结果表明，LHRHa、匹莫齐特和 OHP 的联合治疗可以诱导人工成熟的雌性日本鳗鲡排卵。然而，需要进一步的研究来评估用 LHRHa、pimozide 和 OHP 诱导的雌性产生的胚胎的质量。此外，从人工诱导性成熟的雌性鳗鱼中获得的垂体腺适用于研究 Lh 释放的机制。