Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Building 9201, Juliane Maries Vej 24, 2100 Copenhagen Ø, Denmark.
Peptides. 2013 Jul;45:85-90. doi: 10.1016/j.peptides.2013.04.013. Epub 2013 May 4.
Kiss1 mRNA and its corresponding peptide products, kisspeptins, are expressed in two restricted brain areas of rodents, the anteroventral periventricular nucleus (AVPV) and the arcuate nucleus (ARC). The concentration of mature kisspeptins may not directly correlate with Kiss1 mRNA levels, because mRNA translation and/or posttranslational modification, degradation, transportation and release of kisspeptins could be regulated independently of gene expression, and there may thus be differences in kisspeptin expression even in species with similar Kiss1 mRNA profiles. We measured and compared kisspeptin-immunoreactivity in both nuclei and both sexes of rats and mice and quantified kisspeptin-immunoreactive nerve fibers. We also determined Kiss1 mRNA levels and measured kisspeptin-immunoreactivity in colchicine pretreated rats. Overall, we find higher levels of kisspeptin-immunoreactivity in the mouse compared to the rat, independently of brain region and gender. In the female mouse AVPV high numbers of kisspeptin-immunoreactive neurons were present, while in the rat, the female AVPV displays a similar number of kisspeptin-immunoreactive neurons compared to the level of Kiss1 mRNA expressing cells, only after axonal transport inhibition. Interestingly, the density of kisspeptin innervation in the anterior periventricular area was higher in female compared to male in both species. Species differences in the ARC were evident, with the mouse ARC containing dense fibers, while the rat ARC contains clearly discernable cells. In addition, we show a marked sex difference in the ARC, with higher kisspeptin levels in females. These findings show that the translation of Kiss1 mRNA and/or the degradation/transportation/release of kisspeptins are different in mice and rats.
Kiss1 mRNA 及其相应的肽产物 kisspeptins 表达在啮齿动物的两个特定脑区，即前脑室下核 (AVPV) 和弓状核 (ARC)。成熟 kisspeptins 的浓度可能与 Kiss1 mRNA 水平没有直接相关性，因为 kisspeptins 的 mRNA 翻译和/或翻译后修饰、降解、运输和释放可以独立于基因表达进行调节，因此即使在 Kiss1 mRNA 谱相似的物种中， kisspeptin 的表达也可能存在差异。我们测量并比较了大鼠和小鼠两个核中以及两个性别中的 kisspeptin 免疫反应性，并对 kisspeptin 免疫反应性神经纤维进行了定量分析。我们还测定了预先用 colchicine 处理的大鼠的 Kiss1 mRNA 水平和 kisspeptin 免疫反应性。总的来说，我们发现与大鼠相比，小鼠中 kisspeptin 免疫反应性水平更高，而与脑区和性别无关。在雌性小鼠的 AVPV 中存在大量的 kisspeptin 免疫反应性神经元，而在大鼠中，只有在轴突运输抑制后，雌性 AVPV 才会显示出与 Kiss1 mRNA 表达细胞数量相似的 kisspeptin 免疫反应性神经元数量。有趣的是，在前脑室周围区域，雌性的 kisspeptin 支配密度高于雄性。ARC 中的种间差异明显，其中小鼠的 ARC 含有密集的纤维，而大鼠的 ARC 则含有明显可辨别的细胞。此外，我们还显示 ARC 中存在明显的性别差异，雌性的 kisspeptin 水平更高。这些发现表明，在小鼠和大鼠中，Kiss1 mRNA 的翻译和/或 kisspeptins 的降解/运输/释放存在差异。
