Viguié C, Jansen H T, Glass J D, Watanabe M, Billings H J, Coolen L, Lehman M N, Karsch F J
Reproductive Sciences Program, University of Michigan, Ann Arbor, Michigan 48109-0404, USA.
Endocrinology. 2001 Mar;142(3):1317-24. doi: 10.1210/endo.142.3.8000.
The GnRH neurosecretory system undergoes marked structural and functional changes throughout life. The initial goal of this study was to examine the neuroanatomical relationship between GnRH neurons and a glycoprotein implicated in neuroplasticity, the polysialylated form of neural cell adhesion molecule (PSA-NCAM). Using dual label immunocytochemistry in conjunction with confocal microscopy, we determined that fibers, terminals, and perikarya of GnRH neurons in adult ovariectomized ewes are intimately associated with PSA-NCAM. In the preoptic area, intense PSA-NCAM immunoreactivity was evident around the periphery of GnRH cell bodies. The second goal of this study was to determine whether PSA-NCAM expression associated with GnRH neurons varies in conjunction with seasonal changes in the activity of the GnRH neurosecretory system in ovariectomized ewes treated with constant release implants of estradiol. During the breeding season when reproductive neuroendocrine activity was enhanced, the expression of PSA-NCAM immunoreactivity associated with GnRH neurons was significantly greater than that during anestrus when GnRH secretion was reduced. This difference, which occurred despite an unchanging ovarian steroid milieu, was not observed in preoptic area structures devoid of GnRH immunoreactivity, suggesting that the seasonal change is at least partially specific to the GnRH system. The close association between PSA-NCAM and GnRH neurons and the change in this relationship in conjunction with seasonal alterations in GnRH secretion provide anatomical evidence that this molecule may contribute to seasonal remodeling of the GnRH neurosecretory system of the adult.
促性腺激素释放激素（GnRH）神经分泌系统在整个生命过程中会经历显著的结构和功能变化。本研究的最初目标是检查GnRH神经元与一种参与神经可塑性的糖蛋白——神经细胞黏附分子的多唾液酸化形式（PSA-NCAM）之间的神经解剖学关系。通过结合共聚焦显微镜的双重标记免疫细胞化学方法，我们确定成年去卵巢母羊中GnRH神经元的纤维、终末和胞体与PSA-NCAM密切相关。在视前区，GnRH细胞体周围可见强烈的PSA-NCAM免疫反应性。本研究的第二个目标是确定在接受雌二醇缓释植入物治疗的去卵巢母羊中，与GnRH神经元相关的PSA-NCAM表达是否会随着GnRH神经分泌系统活动的季节性变化而变化。在繁殖季节，当生殖神经内分泌活动增强时，与GnRH神经元相关的PSA-NCAM免疫反应性表达显著高于发情间期GnRH分泌减少时。尽管卵巢类固醇环境不变，但在缺乏GnRH免疫反应性的视前区结构中未观察到这种差异，这表明这种季节性变化至少部分是GnRH系统特有的。PSA-NCAM与GnRH神经元之间的密切关联以及这种关系随GnRH分泌的季节性变化而改变，提供了解剖学证据，表明该分子可能有助于成年GnRH神经分泌系统的季节性重塑。
