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Abstract Although corticosterone (Cort) has been the predominant metric used to assess acute stress in birds, it does not always accurately reflect how an animal copes with a stressor. Downstream measurements may be more reliable. In the current study, we tested the hypothesis that acute increases in DNA damage could be used to assess stressor exposure. Studies have shown DNA damage increases in response to stress‐related hormones in vitro; however, this has not yet been thoroughly applied in wild animals. We exposed house sparrows (Passer domesticus) to a 30‐ or 120‐min restraint stressor and took blood samples at 0, 30, 60, and 120 min to measure Cort, DNA damage, and uric acid. Both treatments increased DNA damage and Cort, and decreased uric acid. It thus appears that DNA damage can reflect acute stressor exposure. To improve the usability of DNA damage as a metric for stress, we also tested the impacts of sample storage on DNA damage. Leaving red blood cells on ice for up to 24 hr, only slightly influenced DNA damage. Freezing blood samples for 1–4 weeks substantially increased DNA damage. These findings emphasize the importance of reducing variation between samples by assaying them together whenever possible. Overall, these results indicate that assessing DNA damage is a valid method of assessing acute stressor exposure that is suitable for both laboratory‐ and field‐based studies; however, additional research is needed on the molecular dynamics of nucleated red blood cells, including whether and how their DNA is repaired.
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This content will become publicly available on March 24, 2026
Corticosterone and Mitochondrial Efficiency Are Associated With Changes in DNA Oxidative Damage During an Acute Stress Response in Leach's Storm‐Petrels ( Hydrobates leucorhous )
ABSTRACT The ability of organisms to effectively respond to challenges is critical for survival. We investigated how an acute stressor affected corticosterone, mitochondrial function, and DNA oxidative damage in a wild population of Leach's storm‐petrels (Hydrobates leucorhous). We conducted a standardized 20‐min handling procedure on storm‐petrel chicks and collected baseline and post‐handling blood samples. We measured plasma corticosterone and red blood cell DNA oxidative damage levels through the detection of a mutated DNA base 8‐Hydroxy‐2'‐deoxyguanosine (8‐OHdG). In addition, we quantified six measures of mitochondrial aerobic metabolism from red blood cells. Overall, the handling stressor increased plasma corticosterone levels and decreased mitochondrial efficiency to produce ATP. Although the increase in corticosterone was inversely related to the change in DNA oxidative damage, the decrease in mitochondrial efficiency was positively correlated with the change in DNA oxidative damage. Thus, over an acute stress response, individuals who had the largest increase in corticosterone also had the least amount of oxidative damage. In addition, individuals who prioritized ATP production during the acute stress also showed higher levels of oxidative damage. This work highlights the complex pathways by which corticosterone and mitochondrial efficiency affect oxidative damage during acute stress, providing new insights into the trade‐offs underlying physiological responses in wild animals.
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- PAR ID:
- 10648282
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Journal of Experimental Zoology Part A: Ecological and Integrative Physiology
- ISSN:
- 2471-5638
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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