This research will uncover the neural (brain) mechanisms that govern behaviors related to food appetite and the motivation to engage in reproductive activities. A wide variety of chemical substances, such as the fat cell hormone leptin, have been identified as potential satiety signals, despite research from this laboratory showing that leptin is a potent stimulators of reproductive activity. When animals have an unforced choice between foraging for food and mating partners, leptin treatment increases interest in mating partners at doses that fail to decrease food intake. These results are interpreted in light of evolution by natural selection, that is, the idea that traits are maintained in populations over generations if they increase reproductive success. Energy consumption (food intake) is critical for the energetically expensive processes related to reproduction, and so brain processes that increase food intake are directly linked to reproductive success. Similarly, the brain structures that inhibit hunger and ingestive behavior might be most adaptive when these structures cause individuals to stop foraging, hoarding and eating in order to find and court potential mates. This project will be used to study blood fluctuations after food deprivation and re-feeding in leptin, insulin and ghrelin while also examing brain levels of neuropeptide Y, corticotropin releasing hormone, kisspeptin, and gonadotropin inhibiting hormone, the typical chemical messengers that are candidates for mediating the effects of food deprivation on reproduction and eating. It is expected that those peptides that fail to change prior to the changes in behavior will be eliminated as candidates, and this, in turn, will allow focused research on those peptides that change in time to account for changes in behavior. These results will facilitate our understanding of worldwide obesity and the training of both graduate and undergraduate students in our behavioral neuroscience programs.
