Meeting Abstract

4-1  Monday, Jan. 4 08:00  Seasonal Variation and Correlation between Corticosterone and the Antioxidant Uric Acid During Stress in the Northern Cardinal (Cardinalis cardinalis) WALKER, B.G.*; HASKINS, J.W.; SPIZOUCCO, F.A.; Fairfield University; Fairfield University; Fairfield University bwalker@fairfield.edu

Glucocorticoids modify metabolism in order to mount a response to stressors. In passerines, this response is affected by a combination of seasonal changes, life-history events, and environmental factors. Knowing the connection between stress hormones and metabolism is fundamental in understanding normal seasonal physiological changes. We evaluate seasonal variation in the acute corticosterone stress response of Northern Cardinals (Cardinalis cardinalis) and if this response correlates with the antioxidant marker uric acid. Baseline corticosterone, δ₁₀CORT, and total stress response were significantly different between seasons. For all three corticosterone measurements (baseline, δ₁₀CORT, and total) birds captured in summer consistently had the lowest values while spring birds had the highest. The difference in corticosterone between spring and summer may reflect a physiological reduction of stress response meant to protect the investment in eggs/chicks being reared in the summer. High corticosterone in the spring may result from breeding and nesting during a period of abundant resources and mates in which nest abandonment due to an acute stressor is less costly. Plasma uric acid, an end product of protein metabolism with known antioxidant effects, was monitored to test for a correlation between corticosterone induced stress and metabolic activity. While plasma uric acid significantly decreased over 60 minutes independent of season, there was no significant correlation with corticosterone. We conclude there are physiologically relevant seasonal fluctuations in corticosterone in the Northern Cardinal and an indirectly related decrease in uric acid during acute stress.