ABSTRACT IBN 97-28032 PI = THOMPSON, ROBERT C. Regulation of Reproductive and Stress Axes by the Metabolic Signal, Leptin Food availability affects reproductive function. Key to understanding as well as many other bodily functions, lies in our ability to understand how the brain gathers information on the availability of food. A major gap in our understanding of how food availability controls reproduction was filled recently with the discovery of a hormone called leptin. Blood leptin concentrations increase after meals in most animals reporting to the brain a satiety signal. Exactly how the brain senses these satiety signals like leptin is only beginning to be understood. Dr. Thompson will determine how the brain senses leptin and more specifically, communicates this leptin information to brain centers that control reproductive function. One hypothesis tested in this research plan is that information about altered food availability is relayed to the reproductive brain centers via brain centers that are involved in sensing "stress". This idea arose when researches from different backgrounds demonstrated two points. First, stress or stressful experiences have negative effects upon reproductive systems. Second, during conditions where food availability is very low, brain systems known to control stress are activated. Thus, conditions where food is in very short supply are stressful. However, little is known if the activation of these stress systems is the path by which information concerning severely reduced food availability is communicated to reproductive systems. This will be examined in this project. Additionally, many molecules in addition to leptin serve as "food signals". One other signal is glucose. Do different food signals communicate to the reproductive system using the same pathways or are there unique pathways for each food signal? Using similar logic, are all stressful situations or conditions influence d by food signals? Dr. Thompson will explore these questions and information developed in this work will be used to further understand how the brain uses food information to control reproductive function.
