Meeting Abstract

P2.115  Jan. 5  The effect of chronic stress on glucocorticoid concentration and metabolism CYR, N.E.*; ROMERO, L.M.; Tufts University; Tufts University npoiri01@tufts.edu

Changes in glucocorticoid concentrations during acute stress act to mobilize energy, which enables the animal to survive stressful events. However, chronic changes in glucocorticoid concentration and metabolism can lead to disease. We studied the effect of chronic stress on corticosterone (CORT, the avian glucocorticoid), corticosterone binding globulin (CBG), insulin, glucose, and triglyceride concentrations in European starlings, Sturnus vulgaris. We found that total CORT decreased throughout the CSP. CORT�s binding protein, CBG, binds circulating CORT with high affinity in birds, and it is currently unknown whether the proportion of CORT bound to CBG results in an increase or decrease in active CORT. Therefore, we measured total CORT concentrations as well as free, unbound, CORT concentrations. In our birds, CBG did not significantly change with chronic stress, thus free CORT followed the same pattern of attenuation with chronic stress. Despite the decrease in CORT, glucose did not change with chronic stress. Insulin and triglyceride concentrations also remained constant throughout our CSP. Our CSP altered CORT, but did not affect glucose or triglyceride levels suggesting that our birds may have adapted to the CSP. Alternatively, the CORT response to chronic stress may be decoupled from it�s actions over metabolism in order to mitigate metabolic costs to chronic stress.