Energetic Regulation of Puberty

在所有脊椎动物中，一种与生殖有关的重要化合物是促性腺激素释放激素（GnRH）。这种肽在大脑的神经细胞中产生，并调节垂体激素的合成和释放，从而刺激排卵。这种哺乳动物的祖先是一种类似鼩鼱的动物，一些鼩鼱物种今天仍然没有卵巢或行为发情周期，青春期是由交配开始的，而不是像大多数其他哺乳动物那样由卵巢激素开始的。在一种叫做麝香鼩的物种中，第一次交配会引发前脑GnRH的快速变化，多次交配会引发排卵。鼩鼱有非常高的新陈代谢，很大程度上是独居的“机会主义”繁殖者，繁殖受当地环境条件的进一步调节，特别是食物的供应，独立于性激素周期。在包括灵长类动物在内的许多哺乳动物中，至少有两种形式的GnRH，一种可能主要调节排卵，另一种可能调节行为。本项目利用免疫细胞化学和分子技术，以麝香鼩为独特的模型，探索交配和食物摄入如何影响大脑中两种形式的GnRH的功能，以调节性行为和青春期。这项工作的影响将从神经科学扩展到生殖内分泌学，以及比较和进化生物学。此外，该项目将支持一个独特的动物种群作为国家资源，并将支持神经内分泌学的学生培训。

An important compound involved in reproduction in all vertebrate species is gonadotropin-releasing hormone, GnRH. This peptide is produced in nerve cells of the brain, and regulates synthesis and release of pituitary hormones, which in turn stimulate ovulation. The ancestral mammal was a shrew-like animal, and some shrew species today still lack an ovarian or behavioral estrous cycle, and puberty is initiated by mating rather than by ovarian hormones as in most other mammals. In a species called the musk shrew, the first mating triggers rapid changes in GnRH in the forebrain, and multiple matings initiate ovulation. Shrews have very high metabolism, are largely solitary 'opportunistic' breeders, and reproduction is further regulated by local environmental conditions, particularly food availability, independent of sex hormone cycles. In many mammals including primates, there are at least two forms of GnRH, and one may primarily regulate ovulation, and the other may regulate behavior. This project uses immunocytochemical and molecular techniques with the musk shrew as a unique model to explore novel issues of how mating and food intake affect the functions of the two forms of GnRH in the brain, to regulate sexual behavior and puberty. The impact of this work will extend beyond neuroscience to reproductive endocrinology, and to comparative and evolutionary biology. In addition, this project will support a unique animal colony as a national resource, and will support student training in neuroendocrinology.