PI: Grober, M. IBN-9723817 The long term goal of this research is to understand social regulation of reproductive function. In the bluehead wrasse, social interactions regulate the expression of a wide range of reproductive options, specifically the transformation of both females and males into a 'supermale' reproductive morph; i.e., gender change. This unique fish provides a model system for understanding social regulation of reproductive neuroendocrinology for several reasons: 1) the precise timing of reproductive transitions can be experimentally controlled, 2) behavioral changes occur within minutes of the social trigger and total gender reversal can be completed in eight days, 3) gender transitions result in permanent changes in reproductive behavior, and 4) these differences in behavior result from and/or cause permanent changes in the brain and endocrine system. To approach our long term goal, one central hypothesis will be addressed: Changes in social status induce changes in forebrain Arginine Vasotocin (AVT) centers and gonadal hormone levels, which in turn generate changes in the social and reproductive behaviors that are a necessary component of gender change. This project will focus on AVT because brain centers that produce this peptide hormone exhibit several key characteristics: 1) in many vertebrate species, males and females show dramatic differences in these cells, 2) these cells are sensitive to social modulation and gonadal hormone levels, 3) this peptide regulates social and mating behavior in association with levels of specific gonadal hormones, and 4) these cells undergo rapid and directional changes during gender reversals in the bluehead wrasse. This proposal addresses four specific aims: 1. The precise timing of changes in gender-specific behavior must be determined. 2. These results will be used as a timeline for examining the timing relationship between changes in behavior and changes in the brain cells during gender change. 3. Determination of changes in gonadal hormones that accompany gender change before, during and after gender change. 4. Determination of the affects of gonadal hormones on forebrain AVT cells. Recent changes in average testosterone levels in men and infertility in women are associated with changes in our own social associations. A general understanding of these processes may be gained from the investigation of the social control of reproduction in a range of vertebrates; the bluehead wrasse is a good model system for such studies. This work will provide a detailed picture of how social interactions regulate reproductive behavior, neurobiology and endocrinology. As an RUI proposal, this project will foster the participation of undergraduates in an integrative research program. Students will learn to critically read scientific literature, generate hypotheses and methods for testing these hypotheses, predict possible outcomes, and analyze / discuss their results. In addition, students will get experience with state-of-the-art technologies in biological sciences increasing the range of future opportunities for these students, and their ability to succeed in these fields. Our program caters to undergraduates with non-traditional backgrounds and the goal of this project is to make these students competitive for openings in top quality graduate and professional programs.
