My lab is looking at testing cortisol levels in mice with EAE, and we are looking at doing so in the most non invasive manner. Our plan is to run a cortisol ELISA on the fecal pellets. My question is, is there a way that these fecal pellets can be stored?
We don't do cortisol levels, but we typically store mouse fecal pellets in bead basher tubes or regular epps. at -80C. We are often looking at IgA levels. I don't know for certain but I expect cortisol to be stable at -80C and freeze/thaw. We freeze immediately after collection of "fresh" pellets on dry ice and then transfer to -80C for long term storage.
Importantly - can you detect measurable cortisol in fecal pellets? Do you think handling the mice will alter cortisol (perhaps just in blood but not feces)? I'm curious to know how it works out. Good luck!