Meeting Abstract
All organisms experience stressors, and the physiological response to stress is highly conserved in vertebrates. Acute stress activates the hypothalamus pituitary-adrenal axis, increasing glucocorticoids (CORT), and promoting glucose mobilization. While this is a generalized phenomenon in mammals, a number of factors, ranging from time of day to blood loss, can change the extent to which acute stress leads to hyperglycemia in birds. Here we characterized the glycemic response to acute-handling stress in a free-living population of white-crowned sparrows (WCSP: Zonotrichia leucophrys ) in Tioga Pass Meadow, California. We quantified blood glucose in two groups of WCSP: 1) WCSP serially bled at baseline (within 3 min of capture), at 15 min, and at 30 min post-capture and 2) WCSP held for 30 min and bled at 30 min. We found that acute-handling stress elevated blood glucose at both 15 and 30 min post-capture as compared to baseline. Furthermore, there was no difference between blood glucose levels at 30 min in WCSP from group 1 vs. group 2, handling for thirty min without bleeding had the same hyperglycemic effect as handling with serial bleeds. Next, we will examine the glucocorticoid response to stress, including quantification of corticosterone binding globulin (CBG) levels, to determine which predictive variable: baseline CORT, stress-induced CORT, CBG, free CORT, body condition and/or time spent in traps, best predicts variation in stress-induced hyperglycemia.
