Meeting Abstract

P2.175  Thursday, Jan. 5  Effects of chronic stress on ketone and uric acid levels in juvenile Passer domesticus BAUER, C.M.*; KOPLIK, L.; ROMERO, L.M.; Tufts University; Universidad de Puerto Rico; Tufts University

The stress response is partially mediated by increased levels of circulating glucocorticoids. While the stress response may be adaptive in the short term, chronically elevated levels of glucocorticoids can be pathological. Chronic stress is caused by homeostatic overload; meaning the mediators (glucocorticoids) start to cause the problems themselves. Some of these problems include immunosuppression, diabetes, and muscle breakdown. We aimed to verify that chronic stress is caused by homeostatic overload by monitoring ketone (evidence of fat breakdown) and uric acid (evidence of protein breakdown) concentrations in chronically stressed juvenile house sparrows (HOSPs). HOSPs were chronically stressed for three weeks by applying a series of rotating mild psychological stressors. One group of birds received injections of a glucocorticoid blocker (mitotane) halfway through the chronic stress period to test whether glucocorticoid levels are responsible for protein and fat metabolic product levels. We found that both baseline and stress-induced corticosterone (CORT) levels decreased in all birds after the onset of the chronic stress period. Mitotane birds further decreased their CORT levels after receiving mitotane injections. Towards the end of the chronic stress period, control birds decreased in weight compared to mitotane birds. Contrary to our expectations, we saw no differences in ketone or uric acid levels between control and mitotane birds. In conclusion, corticosterone does appear to mediate the stress-induced decrease in weight, but the mechanism does not appear to involve increased protein or lipid metabolism.