Department of Psychology, Helen Wills Neuroscience Institute, University of California Berkeley, CA, USA.
Front Endocrinol (Lausanne). 2012 May 21;3:60. doi: 10.3389/fendo.2012.00060. eCollection 2012.
Female reproduction requires the precise temporal organization of interacting, estradiol-sensitive neural circuits that converge to optimally drive hypothalamo-pituitary-gonadal (HPG) axis functioning. In mammals, the master circadian pacemaker in the suprachiasmatic nucleus (SCN) of the anterior hypothalamus coordinates reproductively relevant neuroendocrine events necessary to maximize reproductive success. Likewise, in species where periods of fertility are brief, circadian oversight of reproductive function ensures that estradiol-dependent increases in sexual motivation coincide with ovulation. Across species, including humans, disruptions to circadian timing (e.g., through rotating shift work, night shift work, poor sleep hygiene) lead to pronounced deficits in ovulation and fecundity. Despite the well-established roles for the circadian system in female reproductive functioning, the specific neural circuits and neurochemical mediators underlying these interactions are not fully understood. Most work to date has focused on the direct and indirect communication from the SCN to the gonadotropin-releasing hormone (GnRH) system in control of the preovulatory luteinizing hormone (LH) surge. However, the same clock genes underlying circadian rhythms at the cellular level in SCN cells are also common to target cell populations of the SCN, including the GnRH neuronal network. Exploring the means by which the master clock synergizes with subordinate clocks in GnRH cells and its upstream modulatory systems represents an exciting opportunity to further understand the role of endogenous timing systems in female reproduction. Herein we provide an overview of the state of knowledge regarding interactions between the circadian timing system and estradiol-sensitive neural circuits driving GnRH secretion and the preovulatory LH surge.
女性生殖需要精确的时间组织相互作用的、雌激素敏感的神经回路，这些神经回路汇聚在一起，以最佳地驱动下丘脑-垂体-性腺 (HPG) 轴的功能。在哺乳动物中，前下丘脑视交叉上核 (SCN) 中的主生物钟起搏器协调生殖相关的神经内分泌事件，以最大限度地提高生殖成功。同样，在生育期短暂的物种中，生物钟对生殖功能的监督确保了雌激素依赖性的性动机增加与排卵相吻合。在包括人类在内的所有物种中，生物钟时间的打乱（例如，通过轮班工作、夜班工作、睡眠卫生不良）导致排卵和生育能力明显下降。尽管昼夜节律系统在女性生殖功能中起着既定的作用，但这些相互作用背后的特定神经回路和神经化学介质尚未完全了解。迄今为止，大多数工作都集中在 SCN 与促性腺激素释放激素 (GnRH) 系统之间的直接和间接通讯上，以控制促黄体生成素 (LH) 峰的排卵前激增。然而，在 SCN 细胞中在细胞水平上产生昼夜节律的相同时钟基因也常见于 SCN 的靶细胞群，包括 GnRH 神经元网络。探索主时钟与 GnRH 细胞及其上游调制系统中的从属时钟协同作用的方法代表了进一步了解内源性计时系统在女性生殖中的作用的一个令人兴奋的机会。本文综述了关于昼夜节律计时系统与雌激素敏感的神经回路相互作用的知识状态，这些神经回路驱动 GnRH 分泌和排卵前 LH 激增。
