Meeting Abstract

P2.122  Jan. 5  Evaluation of fecal testosterone and corticosterone in green anoles before and after exposure to an acute stressor WACK, Corina L.*; LOVERN, Matthew B.; Oklahoma State University; Oklahoma State University corinawack@yahoo.com

The typical method of sampling steroids � blood collection � is moderately invasive and inappropriate for repeated sampling in many animals (e.g., due to small size, endangered status). A non-invasive sampling method thus would be desirable for reasons of both experimental design and animal welfare. In addition to their presence in blood, steroids are excreted in feces. Therefore, the goal of our study was to develop and validate a radioimmunoassay (RIA) for detecting fecal steroids in the green anole (Anolis carolinensis), a widely-used reptile model. Reproductively-active males and females were housed under standard lab conditions. Fecal samples were collected from each individual daily, before and after exposure to an acute stressor (capture restraint). Blood samples were collected immediately following the stressor from half of the lizards for comparison to samples collected from non-restrained lizards; fecal samples were collected for an additional three days from the remaining lizards. We determined plasma and fecal levels of testosterone (T) and corticosterone (CORT) by RIA, evaluating several different fecal steroid extraction and isolation techniques. In general, we found higher fecal T or metabolite levels in males and no sex difference in fecal CORT or metabolite levels. These results are consistent with plasma T and CORT profiles, suggesting that fecal steroid RIAs may provide an alternative to blood sampling for measuring steroid profiles in green anoles. However, comparisons between results from plasma and feces following capture restraint were inconsistent, suggesting that fecal steroid RIAs may not be suitable for measuring acute changes in steroid levels.