Excretion of corticosteroids in urine and faeces of hares ( Lepus europaeus )

Abstract

Increased production of glucocorticoids by the adrenal cortex is found in mammals under stress. As cortisol itself is absent in the faeces, an enzyme immunoassay (11-oxoaetiocholanolone) measuring 11,17-dioxoandrostanes has already been established to measure faecal cortisol metabolites in ruminants for non-invasive monitoring of adrenocortical activity. The aim of this study was to establish route and delay of excretion of glucocorticoids in hares and to determine whether a cortisol-, corticosterone- or this new enzyme immunoassay is best suited to detect faecal glucocorticoid metabolites. In the first experiment radioactive-labelled glucocorticoids (14C-cortisol and 3H-corticosterone) were administered intravenously to two groups of three hares in metabolic cages. All voided urine and faecal samples were collected for 4 days. Metabolites of both steroids were found predominantly in the urine (91 +/- 4%). Peak concentrations were observed in the first urinary sample following infusion (13 +/- 6 h) and in the faeces with a delay of about 1 day (23 +/- 7 h). Most of the radioactivity was not extractable with diethylether, indicating that the metabolites excreted in urine and faeces are mainly conjugated or polar unconjugated ones. This was confirmed by reverse-phase high-performance liquid chromatography separations of the metabolites, which also revealed marked differences concerning the metabolism of the two glucocorticoids injected. Compared with the cortisol and the corticosterone enzyme immunoassay, only the group-specific enzyme immunoassay for 11,17-dioxoandrostanes detected high quantities of immunoreactive metabolites. In a second experiment hares (n = 20) were stressed by rousing them three times (5 min, 10 min and another 5 min) with a 20-min break in-between. Faecal samples were collected 2 days before until 4 days after stress and analysed using the 11-oxoaetiocholanolone enzyme immunoassay. After stress significantly (P < 0.001) increased 11,17-dioxoandrostane concentrations were found. Based on these results, measuring 11,17-dioxoandrostanes in faeces enables non-invasive monitoring of disturbances in hares and thus provides a tool for field investigations elucidating the role of stress in hare populations.

A Validation of Extraction Methods for Noninvasive Sampling of Glucocorticoids in Free‐Living Ground Squirrels

“…These responses are similar to the moderate effects of ACTH reported for some ferrets, rhinoceroses, and chinchillas Young et al 2001;Ponzio et al 2004). As additional studies utilize exogenous glucocorticoid stimulants or suppressors, patterns of differential response as a function of species, population, sex, or individual will become more clear (Hubbs et al 2000;Teskey-Gerstl et al 2000;Brown et al 2001;Goymann et al 2001;Hik et al 2001;Young et al 2001). …”

“…Supernatants were reserved and frozen (−80° C) until assayed. We included 100% ethanol in the study to determine whether it increased recovery of metabolites over 80% ethanol (Teskey-Gerstl et al 2000) and to facilitate comparison with method 3.…”

Determining Adrenocortical Activity as a Measure of Stress in African Buffalo (Syncerus caffer) Based on Faecal Analysis

“…As the two group-specific 11-oxoaetiocholanolone EIAs recognize different groups of metabolites, it is not surprising that their suitability varies across species as hormone metabolism is highly species specific. In European (Lepus europaeus) and snowshoe hares (Lepus americanus) for example, the 11,17-DOA EIA appear to be suitable for monitoring adrenocortical function (Teskey-Gerstl et al 2000;Sheriff et al 2009), whereas, for example, in African elephants (Loxodonta africana) and mountain hares (Lepus timidus) only the 3~,11oxo-CM EIA (Ganswindt et al 2003;Rehnus et al 2009), and in goats both EIAs (Kleinsasser et al 2010) reflect adrenocortical activity adequately. Although the EIA measuring 11,17-DOA seems to perform slightly better and was therefore used for all subsequent analyses, both assays would be suited to provide information on the level of stress experienced by African buffalos.…”

Excretion of Steroid Hormones in Rodents: An Overview on Species Differences for New Biomedical Animal Research Models

“…), this genetic proximity would explain these results. Accordingly, low fecal excretion of glucocorticoid metabolites (about 8%) has also been found in European hares (Lepus europaeus; Teskey-Gerstl et al, 2000). In fact, Taylor (1971) informed (another species of Lagomorpha order) that only between 3-5% of testosterone or 4% of estradiol are excreted in rabbit feces.…”