Progestin increases the expression of gonadotropins in pituitaries of male zebrafish.
Progestin increases the expression of gonadotropins in pituitaries of male zebrafish.
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DOI：
10.1530/joe-16-0073
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发表时间：
2016-07
期刊：
影响因子：
--
通讯作者：
Chen SX
中科院分区：
文献类型：
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作者：
Wang C;Liu D;Chen W;Ge W;Hong W;Zhu Y;Chen SX
我们之前的研究表明，斑马鱼的主要孕激素17α,20β-二羟基-4-孕烯-3-酮（DHP）在体内对早期精子发生的积极作用比体外强得多，这可能表明DHP对促性腺激素表达的影响。在我们目前的研究中，我们首先观察到，雄性成年斑马鱼垂体中的 fshb 和 lhb mRNA 水平在暴露于 10 nM 雌二醇 (E2) 3 周后受到极大抑制。然而，额外的 24 小时 100 nM DHP 暴露不仅逆转了 E2 诱导的抑制，而且还显着增加了 fshb 和 lhb mRNA 的表达。在未经 E2 预处理的雄性成鱼中也观察到了这些刺激作用，并且时程实验表明，fshb 需要 24 小时，lhb 需要 12 小时才能显着反应。由于这些刺激活性被核黄体酮受体 (Pgr) 拮抗剂米非司酮部分拮抗，因此我们使用 TALEN 技术生成了 Pgr 敲除 (pgr−/−) 模型。无论是否经过 DHP 体内治疗，pgr−/− 的 fshb 和 lhb mRNA 水平均显着低于 pgr+/+ 的水平。此外，用 DHP 对 pgr−/− 的垂体片段进行离体处理会刺激 lhb mRNA 表达，但不会刺激 fshb mRNA 表达。双色荧光原位杂交结果显示，pgr mRNA仅在表达fshb的细胞中表达。综上所述，我们的结果表明，DHP 参与了雄性斑马鱼生殖神经内分泌控制的调节，并对垂体水平的 fshb mRNA 产生 Pgr 介导的直接刺激作用。
Our previous study showed that the in vivo positive effects of 17α,20β-dihydroxy-4-pregnen-3-one (DHP), the major progestin in zebrafish, on early spermatogenesis was much stronger than the ex vivo ones, which may suggest an effect of DHP on the expression of gonadotropins. In our present study, we first observed that fshb and lhb mRNA levels in the pituitary of male adult zebrafish were greatly inhibited by 3 wk exposure to 10 nM estradiol (E2). However, an additional 24 hr 100 nM DHP exposure not only reversed the E2-induced inhibition, but also significantly increased the expression of fshb and lhb mRNA. These stimulatory effects were also observed in male adult fish without E2 pretreatment, and a time course experiment showed that it took 24 hr for fshb and 12 hr for lhb to respond significantly. Because these stimulatory activities were partially antagonized by a nuclear progesterone receptor (Pgr) antagonist mifepristone, we generated a Pgr-knock out (pgr−/−) model using the TALEN technique. With and without DHP in vivo treatment, fshb and lhb mRNA levels of pgr−/− were significantly lower than those of pgr+/+. Furthermore, ex vivo treatment of pituitary fragments of pgr−/− with DHP stimulated lhb, but not fshb mRNA expression. Results from double-colored fluorescent in situ hybridization showed that pgr mRNA was expressed only in fshb-expressing cells. Taken together, our results indicated that DHP participated in the regulation of neuroendocrine control of reproduction in male zebrafish, and exerted a Pgr-mediated direct stimulatory effect on fshb mRNA at pituitary level.