The Role of Kisspeptin in Female Reproductive Aging

描述（由申请方提供）：本提案旨在评价KiSS-1在雌性大鼠GnRH神经元对雌二醇（E2）反应性的年龄相关变化中的作用。虽然强有力的证据表明KiSS-1和GPR 54对于E2反馈到包括人类在内的许多物种的年轻成年人的GnRH神经元至关重要，但我们几乎不了解这种机制在中年向生殖衰老过渡期间如何变化。以下具体目标将解决这一假设，即KiSS-1神经元对E2的反应性下降在介导衰老雌性大鼠LH峰的幅度降低和延迟中起着关键作用。我们的第一个目标是确定年龄和一天中的时间对KiSS-1的影响。我们将研究KiSS-1和雌激素受体（ER）的KiSS-1神经元的生产，或KiSS-1和ER细胞密度是否随年龄的变化在AVPV。我们将确定KiSS-1基因和蛋白质表达是否存在昼夜变化。此外，我们将研究年龄和一天中的时间对KiSS-1轴突密度的影响，GnRH神经元群体对LH激增至关重要。我们的第二个目的是评估KiSS-1神经元对E2的反应。我们将通过测试E2随年龄激活AVPV中KiSS-1神经元的能力以及确定E2诱导的KiSS-1神经元激活在多大程度上取决于一天中的时间来实现这一目标。此外，我们将确定是否老化，E2，和一天中的时间差异影响GPR 54的终板/吻侧内侧视前核（OVLT/rMPN），一个已知参与产生GnRH/LH浪涌的区域的血管器的GnRH神经元群体的表达。我们的第三个，也是最后一个目标，将是评估年龄和一天中的时间对KiSS-1介导E2诱导的LH峰的能力的影响。在这个目标中，关键是要评估KiSS-1，集中给药，是否会引起中年大鼠的GnRH/LH激增，如果一天中的时间是一个关键因素。此外，我们将确定是否年龄和一天中的时间差异影响的能力，集中管理KiSS-1激活GnRH神经元。中年动物的GnRH神经元可能对KiSS-1的反应较低，因此我们将检查GPR 54表达是否随年龄和时间而变化。从拟议的研究结果将有重要意义的神经内分泌参与的更年期和年龄相关的不孕症的妇女发病的理解。

DESCRIPTION (provided by applicant): This proposal seeks to evaluate the role of KiSS-1 in the age-related changes in responsiveness of GnRH neurons to estradiol (E2) in the female rat. Although strong evidence indicates that KiSS-1 and GPR54 are critical for E2 feedback onto GnRH neurons in young adults across many species including humans, we have virtually no understanding of how this mechanism may change during the middle-age transition towards reproductive senescence. The following specific aims will address the hypothesis that a decline in responsiveness of KiSS-1 neurons to E2 plays a critical role in mediating the reduced magnitude and delay of the LH surge in aging female rats. Our first aim will be to determine the effect of age and time of day on KiSS-1. We will investigate whether the production of KiSS-1 and estrogen receptors (ERs) from KiSS-1 neurons, or KiSS-1 and ER cell density change with age in the AVPV. We will determine whether there is a diurnal variation in KiSS-1 gene and protein expression. Additionally we will examine the effect of age and time of day on KiSS-1 axonal density to GnRH neuronal populations critical for the LH surge. Our second aim will be to evaluate the KiSS-1 neuron response to E2 in the AVPV with age. We will accomplish this aim by testing the capacity of E2 to activate KiSS-1 neurons in the AVPV with age and by determining to what extent E2-induced KiSS-1 neuronal activation depends on time of day. Additionally, we will determine whether aging, E2, and time of day differentially affect GPR54 expression in the GnRH neuronal populations of the organum vasculosum of the lamina terminalis/rostral medial preoptic nucleus (OVLT/rMPN), a region known to be involved in generating the GnRH/LH surge. Our third, and final aim, will be to evaluate the effect of age and time of day on the capacity of KiSS-1 to mediate an E2-induced LH surge. In this aim it will be critical to assess whether KiSS-1, given centrally, will elicit a GnRH/LH surge in middle-aged rats and if time of day is a critical factor. Furthermore, we will determine whether age and time of day differentially affect the capacity of centrally administered KiSS-1 to activate GnRH neurons. It is possible that GnRH neurons of middle-aged animals will be less responsive to KiSS-1, so we will examine if GPR54 expression changes with age and time of day. Findings from the proposed study will have critical implications to the understanding of the neuroendocrine involvement of the onset of menopause and age-related infertility in women.