In all our research, we utilize non-invasive methods of hormone collection from known individuals. Sophisticated methods have been developed for measuring steroid hormones from “excreta” – mainly, urine and feces. Such samples can be collected easily and without disturbing an animal, thereby allowing frequent sampling over long time periods. Moreover, because fecal sampling has been shown to smooth short-term fluctuations and diurnal variation, fecal measures can actually improve the ability to distinguish between normal pulsatile changes and genuine physiological responses to external events. However, only rarely do these methods directly measure the hormone in question. Usually the hormone of interest is virtually absent in feces, and methods that measure fecal steroids are actually measuring one to several downstream products of hormone metabolism. Consequently, any method of extracting steroid hormones from “excreta” must be properly validated both analytically and biologically prior to measuring hormone metabolites in a new species. The Beehner endocrine lab at UM uses environmentally friendly and sustainable lab practices when possible.

Much of our research has focused on validating the hormone extraction methods we use, while also trying to improve them. Furthermore, we try to improve upon this method at each stage. For example, we were able to determine that (1) diurnal rhythms do not affect fecal hormones for any of these species, (2) vortexing fecal samples in organic solvent increases hormone recovery, (3) hormones can be stored at ambient temperature for up to 4 weeks prior to freezing, and (4) freeze/thaw cycles should be limited to 1-2 cycles only or hormones are compromised (Beehner & Whitten, 2004; Pappano et al., 2010).