Measuring corticosterone concentrations over a physiological dynamic range in female rats

• Type of Material: Article
• Authors: Mandakh Bekhbat, Emory University; Erica R. Glasper, University of Maryland; Sydney A. Rowson, Emory University; Sean D. Kelly, Emory University; Gretchen Neigh, Emory University
• Language: English
• Date: 2018-10-01
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2018 Elsevier Inc.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.physbeh.2018.04.033
• Title of Journal or Parent Work: Physiology and Behavior
• ISSN: 0031-9384
• Volume: 194
• Start Page: 73
• End Page: 76
• Grant/Funding Information: This work was supported by the National Institutes of Health (NR014886 and MH110364 to GNN; T32-GM008602 to SAR).
• Keywords: BINDING GLOBULIN; Female; RESPONSES; Rat; Science & Technology; Forced swim stress; Corticosterone; ELISA; Social Sciences; Behavioral Sciences; Radioimmunoassay; Psychology; STRESS; Psychology, Biological; Life Sciences & Biomedicine
• Research Categories: Biology, Anatomy; Psychology, Behavioral; Biology, Physiology

Abstract

Accurate assessment of plasma corticosterone, the primary stress hormone in rodents, is an essential part of characterizing the stress response in experimental animals. To this end, both enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay (RIA) remain widely used. However, considerable assay-specific variability exists among commercially available corticosterone assays due to differing assay principles, detection methods, range, and sensitivity. While technical comparisons of commercially available corticosterone assays have previously been conducted, the ability to detect acute stress-induced endocrine changes has not been compared among these methods to date. Using the forced swim test, a commonly utilized behavioral paradigm in rodents as a physiologically-relevant acute stress challenge, we compared four commercial corticosterone assays – three ELISA kits and one RIA kit – in their ability to detect corticosterone across a dynamic range of both baseline and acute swim stress-driven concentrations. While all methods yielded results that were consistent at measuring relative differences between samples, only two of the four assays evaluated detected a statistically significant increase in corticosterone in rats exposed to acute swim stress compared to rats at baseline. The ELISA kit from Enzo Life Sciences demonstrated the greatest percent increase in plasma corticosterone from baseline to acute stress conditions. The RIA kit from MP Biomedicals also detected a significant corticosterone increase and yielded higher concentrations of corticosterone both at baseline and in the acute stress condition relative to the other three assays. We conclude that choice of assay can impact interpretation of data due to differences in efficacy across a dynamic range of physiological concentrations of corticosterone.