Photoperiod and reproductive condition are associated with changes in RFamide-related peptide (RFRP) expression in Syrian hamsters (Mesocricetus auratus).
Photoperiod and reproductive condition are associated with changes in RFamide-related peptide (RFRP) expression in Syrian hamsters (Mesocricetus auratus).
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DOI：
10.1177/0748730410368821
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发表时间：
2010-06
影响因子：
3.5
通讯作者：
Kriegsfeld LJ
中科院分区：
文献类型：
--
作者：
Mason AO;Duffy S;Zhao S;Ubuka T;Bentley GE;Tsutsui K;Silver R;Kriegsfeld LJ
为了在冬季保存稀缺的能量资源，季节性饲养者会抑制繁殖和其他非必要的行为和生理过程。生殖停止是为了应对日照长度的缩短而启动的，这种刺激主要表现为长期褪黑激素信号。褪黑激素信号不是由生殖轴直接解码，而是由促性腺激素释放激素 (GnRH) 上游的未知神经化学系统解码。尽管解码光周期信息的特定细胞表型仍然未知，但下丘脑背内侧核（DMH）与叙利亚仓鼠（Mesocricetus auratus）生殖功能的季节性变化有关。 RFamide 相关肽（RFRP；在鸟类中发现的促性腺激素抑制激素 (GnIH) 基因的哺乳动物同源物）已成为生殖轴的有效抑制调节剂，并且值得注意的是，其表达定位于啮齿动物的 DMH 细胞体。在本研究中，作者探讨了 RFRP 表达、光周期暴露和生殖状况/激素状态之间的关系。在对短日照产生生殖抑制反应的雄性仓鼠中，相对于长日照动物，RFRP-ir 和 mRNA 表达显着降低。短日照动物中睾酮的替代不会影响这种反应，这表明 RFRP 表达的改变不是性类固醇浓度变化的结果。忽略日照长度线索并在短日照中保持生殖能力的仓鼠群体子集（无反应者）表现出与长日照仓鼠相当的 RFRP-ir 表达。对细胞体和纤维密度的分析表明，在生殖退化的早期和晚期阶段，肽的产生和释放速率在差异调节生殖轴方面存在潜在的相互作用。总之，目前的研究结果表明，光周期诱导的繁殖抑制与 RFRP 和 mRNA 表达的变化有关，为进一步探索 RFRP 在此过程中的作用提供了机会。
To conserve scarce energetic resources during winter, seasonal breeders inhibit reproduction and other nonessential behavioral and physiological processes. Reproductive cessation is initiated in response to declining day lengths, a stimulus represented centrally as a long-duration melatonin signal. The melatonin signal is not decoded by the reproductive axis directly, but by an unidentified neurochemical system upstream of gonadotropin-releasing hormone (GnRH). The dorsomedial nucleus of the hypothalamus (DMH) has been implicated in seasonal changes in reproductive function in Syrian hamsters (Mesocricetus auratus), although the specific-cell phenotype decoding photoperiodic information remains unknown. RFamide-related peptide (RFRP; the mammalian homolog of the gonadotropin-inhibitory hormone (GnIH) gene identified in birds) has emerged as a potent inhibitory regulator of the reproductive axis and, significantly, its expression is localized to cell bodies of the DMH in rodents. In the present study, the authors explored the relationship between RFRP expression, photoperiod exposure, and reproductive condition/hormonal status. In male hamsters that respond to short days with reproductive inhibition, RFRP-ir and mRNA expression are markedly reduced relative to long-day animals. Replacement of testosterone in short-day animals did not affect this response, suggesting that alterations in RFRP expression are not a result of changing sex steroid concentrations. A subset of the hamster population that ignores day length cues and remains reproductively competent in short days (nonresponders) exhibits RFRP-ir expression comparable to long-day hamsters. Analysis of cell body and fiber density suggests a potential interplay between peptide production and release rate in differentially regulating the reproductive axis during early and late stages of reproductive regression. Together, the present findings indicate that photoperiod-induced suppression of reproduction is associated with changes in RFRP and mRNA expression, providing opportunity for further exploration on the role that RFRP plays in this process.