Chi Liang, Li Xian, Liu Qinghua, Liu Ying
Center of Biotechnology R&D, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, P.R. China.
College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, P.R. China.
PLoS One. 2017 Feb 15;12(2):e0169569. doi: 10.1371/journal.pone.0169569. eCollection 2017.
Atlantic salmon exhibit seasonal reproduction. However, the mechanisms governing this are still unclear. Generally speaking, kisspeptin has been recognized as a regulator of reproduction. Here, we report a relationship between kisspeptin, GnRH and photoperiod in Atlantic salmon. The results demonstrated that the expression of the Atlantic salmon kisspeptin-receptor (skissr) was not always consistent with the expression pattern of Atlantic salmon GnRH3 (sGnRH3) during all developmental processes. Kisspeptin may exert its influence primarily in the early and later stages of gonad development by promoting the secretion of sGnRH3. Meanwhile, the expression levels of kissr were higher in fish with gonads at stage II and stage V under the long-day photoperiod regime than under the short-day regime. In addition, both skissr and sGnRH3 were also expressed in the saccus vasculosus (SV), an organ only found in fish. The SV might be a seasonal sensor regulating reproduction in addition to the hypothalamus (Hyp).
大西洋鲑表现出季节性繁殖。然而，其背后的调控机制仍不清楚。一般来说， kisspeptin被认为是一种生殖调节因子。在此，我们报告了大西洋鲑中kisspeptin、促性腺激素释放激素（GnRH）和光周期之间的关系。结果表明，在整个发育过程中，大西洋鲑 kisspeptin受体（skissr）的表达并不总是与大西洋鲑GnRH3（sGnRH3）的表达模式一致。Kisspeptin可能主要通过促进sGnRH3的分泌，在性腺发育的早期和后期发挥作用。同时，在长日照光周期条件下，性腺处于II期和V期的鱼中，kissr的表达水平高于短日照条件下。此外，skissr和sGnRH3也在血管囊（SV）中表达，血管囊是一种仅在鱼类中发现的器官。除下丘脑（Hyp）外，血管囊可能是调节繁殖的季节性传感器。
