Meeting Abstract
How does the vertebrate brain regulate sexual and reproductive behaviors? Gonadotropin-releasing hormone (GnRH-I) and gonadotropin-inhibitory hormone (GnIH) are key hypothalamic hormones that mediate vertebrate reproductive endocrinology, yet we have much to learn regarding how their actions affect and are affected by behavior. This type of information is particularly lacking for GnIH, due to its relatively recent discovery in 2000. First, I will review how these peptides vary in cell abundance and gene expression in accordance with reproductive stage in birds and mammals. In seasonally breeding European starlings (Sturnus vulgaris), GnRH-I and GnIH cell bodies are most abundant in males and females during the breeding season (spring) as opposed to the non-breeding period (fall), indicating increased function during this time. Then I will present how changes in GnIH peptide cell abundance, soma size, and peptide concentration are associated with changes in social and ecological cues during the breeding season in European starlings. GnIH peptide cell abundance also changes at the onset of parental care in European starlings and female rats (Rattus norvegicus). These observations provide a powerful base from which to generate and test hypotheses experimentally, clarifying the role of GnRH-I and GnIH in sexual and reproductive behaviors. Finally, I will introduce the common pigeon (Columbia livia) as a powerful model to advance these investigations. Specifically, I will report validated methodology in pigeons that will help elucidate the rapid effects that GnRH-I, GnIH, and other neural substrates have in response to changes in social, reproductive and ecological environments.
