Mary Dallman, Ph.D.

We study the role of the adrenocortical system on hypothalamic regulation of feeding behavior and metabolism and the role of chronic stress on brain pathways regulating adreno-cortical, autonomic and behavioral responses to novel stressors. Because glucocorticoid (GC) recep-tors exist in every tissue type, changes in autonomic activity, energy balance and behavior that occur with either GC treatment or chronic stress may be either directly related to GC action in the tissue studied or secondary to a GC effect on another process. We use increased expression of the immediate early gene, c-fos, to determine where in brain changes occur in response to stress and/or steroid treatment, and identify the responsive cell type using combined in situ hybridization. Additionally, we use tracing techniques to define the relevant pathways involved. Chronic stress appears to alter both central pathways mediating adrenocortical and behavioral responses to acute stress and the disposition of energy so that fat is gained and muscle lost ‹ not good for health. Last, we study genetically modified mice with deficits that alter brain-adrenal activity and energy balance to test specific hypotheses raised by rat work. Our goal is to elucidate the physiology of glucocorticoids and stress on function.