Plasticity of the reproductive axis caused by social status change in an african cichlid fish: I. Pituitary gonadotropins.
Plasticity of the reproductive axis caused by social status change in an african cichlid fish: I. Pituitary gonadotropins.
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DOI：
10.1210/en.2010-0875
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发表时间：
2011-04
期刊：
影响因子：
4.8
通讯作者：
Karen P. Maruska;B. Levavi-Sivan;J. Biran;R. Fernald
中科院分区：
文献类型：
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作者：
Karen P. Maruska;B. Levavi-Sivan;J. Biran;R. Fernald
社会地位在统治阶层中的地位往往与生育率密切相关。因此，能够识别并迅速利用机会提升排名的动物将具有繁殖优势。所有脊椎动物的繁殖都是由脑-垂体-性腺轴控制的，而在雄性非洲慈鱼Astatotilapia burtoni中，位于这一轴顶端的GnRH1神经元受到社会控制。然而，关于社会信息转化为功能性生殖变化的速度有多快，或者GnRH1神经元的社会控制变化如何影响脑-垂体-性腺轴的下游活动，人们知之甚少。我们为生殖受抑的雄性创造了一个提升地位的机会，然后测量了对这个机会的感知导致垂体促性腺激素的mRNA和蛋白质水平变化的速度。在被抑制的雄性觉察到有机会上升后30分钟，垂体中促黄体生成素和卵泡刺激素的β亚单位的基因水平迅速上升。相反，GnRH受体-1的mRNA水平在社会转型过程中保持不变，但稳定优势组的GnRH受体-1水平高于从属男性。在血液循环中，促黄体生成素和促卵泡刺激素水平也迅速升高。促性腺激素、促性腺激素与血浆11-酮睾酮水平呈正相关。我们的结果表明，在感知到社会机会后，脑下垂体受到极快的刺激，这可能是为了让被压抑的雄性在动态的社会环境中迅速获得生殖成功。
Social position in a dominance hierarchy is often tightly coupled with fertility. Consequently, an animal that can recognize and rapidly take advantage of an opportunity to rise in rank will have a reproductive advantage. Reproduction in all vertebrates is controlled by the brain-pituitary-gonad axis, and in males of the African cichlid fish Astatotilapia burtoni, GnRH1 neurons at the apex of this axis are under social control. However, little is known about how quickly social information is transformed into functional reproductive change, or about how socially controlled changes in GnRH1 neurons influence downstream actions of the brain-pituitary-gonad axis. We created an opportunity for reproductively suppressed males to ascend in status and then measured how quickly the perception of this opportunity caused changes in mRNA and protein levels of the pituitary gonadotropins. mRNA levels of the β-subunits of LH and FSH rose rapidly in the pituitary 30 min after suppressed males perceived an opportunity to ascend. In contrast, mRNA levels of GnRH receptor-1 remained unchanged during social transition but were higher in stable dominant compared with subordinate males. In the circulation, levels of both LH and FSH were also quickly elevated. There was a positive correlation between mRNA in the pituitary and circulating protein levels for LH and FSH, and both gonadotropins were positively correlated with plasma 11-ketotestosterone. Our results show that the pituitary is stimulated extremely rapidly after perception of social opportunity, probably to allow suppressed males to quickly achieve reproductive success in a dynamic social environment.