Energetic Regulation of Puberty

University Of Virginia Main Campus, Charlottesville VA

Investigators

Abstract

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.