Effects of gonadotropin-releasing hormone agonist and dopamine antagonist on hypothalamus-pituitary-gonadal axis of pre-pubertal female red seabream (Pagrus major)
Effects of gonadotropin-releasing hormone agonist and dopamine antagonist on hypothalamus-pituitary-gonadal axis of pre-pubertal female red seabream (Pagrus major)
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DOI：
10.1016/s0016-6480(03)00012-1
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发表时间：
2003-05-01
影响因子：
2.7
通讯作者：
Kagawa, H
中科院分区：
文献类型：
--
作者：
Kumakura, N;Okuzawa, K;Kagawa, H
研究了 GnRH 激动剂 (GnRHa) 对青春期前雌性红鲷下丘脑-垂体-性腺轴的影响。将性成熟的16月龄鱼肌内植入含有GnRHa或GnRHa与多潘立酮（推定的多巴胺拮抗剂）组合的胆固醇颗粒，并饲养10-20天。在GnRHa和GnRHa+多潘立酮植入组中，在第10天观察到卵黄发生，在第20天观察到排卵，而在整个实验期间对照鱼中没有观察到卵巢发育。两个 GnRHa 植入组的 GnRH 受体 mRNA 水平均显着高于对照组。 GnRHa 植入后，所有三个促性腺激素亚基基因的表达均上调，并且血清黄体生成素水平升高。血清睾酮和雌二醇-17β水平在第10天也有所增加，并在第20天保持高水平。另一方面，所有实验组中鲷鱼(sb)脑中GnRH mRNA水平相对较低且没有变化。本研究首先表明，单独使用 GnRH 可以诱导红鲷性早熟。这些结果表明，16月龄鱼的垂体-性腺轴系统已经发育，sbGnRH分泌的开始可能是红鲷青春期开始的重要生理事件。 (C) 2003 年爱思唯尔科学（美国）。版权所有。
The effects of GnRH agonist (GnRHa) on the hypothalamus-pituitary-gonadal axis were studied in female pre-pubertal red seabream. Sexually immature 16-month-old fish were implanted intramuscularly with cholesterol pellets containing GnRHa or GnRHa in combination with domperidone, putative dopamine antagonist, and reared for 10-20 days. In both GnRHa and GnRHa + domperidone implanted groups, vitellogenesis was observed on Day 10 and ovulation was observed on Day 20, while ovarian development was not observed in the control fish throughout the experimental period. The levels of GnRH receptor mRNA were significantly higher in both GnRHa implanted groups than in the control. The expressions of all three gonadotropin subunit genes were up-regulated and serum luteinizing hormone levels were increased by the GnRHa implantation. Serum testosterone and estradiol-17beta levels were also increased on Day 10 and maintained high levels on Day 20. On the other hand, seabream (sb) GnRH mRNA levels in the brain were relatively low and unchanged in all experiment groups. The present study first shows that GnRH alone can induce precocious puberty in red seabream. These results indicate that the system of pituitary-gonadal axis has already been developed in 16-month-old fish and the commencement of sbGnRH secretion may be an important physiological event for the onset of puberty in the red seabream. (C) 2003 Elsevier Science (USA). All rights reserved.