Excretion of corticosteroid metabolites in urine and faeces of rats

Abstract

SummaryStress enhances the production of corticosteroids by the adrenal cortex, resulting in the increased excretion of their metabolites in urine and faeces. An intraperitoneal injection of radioact ive corticosterone was applied to adult, male Sprague-Dawley rats to monitor the route and delay of excreted metabolites in urine and faeces. Peak concentrations appeared in urine after 3.2 1.9 h and in faeces after 16.7 4.3 h. Altogether about 20% of the recovered metabolites were found in urine and about 80% in faeces. Using high-performance liquid chromatography (HPLC ), several peaks of radioacti ve metabolites were found. Some metabolites were detected by enzym e immunoassay (EIA) using two different antibodies (corticosterone, 11b-OH-aet iocholanolone). T here was a marked diurnal variation with low levels of faecal corticosterone metabolites in the evening and higher values in the morning. T his diurnal variation was in¯uenced neither by the intraperitoneal injection of isotonic saline nor by ACT H. However, the administrat ion of dexamethasone eliminated the morning peak for 2 days. Keywords Rat; urine; faeces; corticosterone; ACT H; dexamethasone Adapt at ion to stressful events is associated with an increased production and secretion of glucocorticoids from the adrenal cortex into the blood. Various speci®c and non-speci®c stim uli are able to induce increased secretion of glucocorticoids (Clark e t a l. 1997a,b). When the hypothalam ic-pituit ary-adren al axis is suddenly act ivated, glucocorticoids signi®cantly increase and, in rats, maxim um values are usually seen about 20 min lat er, although the tim e sequence depends on the stim ulus intensity. However, the glucocorticoid concentration in the blood is not an appropriat e indicator of long-term aversive stim ulation, because animals may become less anxious or concerned or may get used to the stim ulus. Also, the feedback regulatory system tends to reduce hormone values (Manser 1992 ). High plasma concentrat ions of glucocorticoids inhibit the release of ACT H from the pituitary gland, which in turn causes a decreased hormone secretion by the adrenal cortex. T herefore, high concentrations of glucocorticoids do not usually persist for a long time (no more than 90 min) in the circulation. Nevertheless, an increase in glucocorticoid concentrations in peripheral blood can represent a sensitive indicator of the intensity of discomfort or distress experienced by the anim als (Van de Kar e t a l. 1991 ).In contrast to the concentration in blood, which is in¯uenced by the stressful sampling itself (Cook e t a l. 1973 ) and which re¯ects a momentary situation, the collection of urine or faeces allows the monitoring of previous

Impact of chronic catheterization and automated blood sampling (Accusampler) on serum corticosterone and fecal immunoreactive corticosterone metabolites and immunoglobulin A in male rats

“…This rather quick return to normality, even if stress persists, has been previously described by Manser (1992). In the present study we recorded an increase of excretion of fecal immunoreactive corticosterone metabolites after the surgery (22 h) compared with the basal levels measured before surgery, and this suggests a delay between serum corticosterone changes and excreted corticosterone and immunoreactive corticosterone metabolites, which is in agreement with the findings of Teskey-Gerstl et al (2000) and Bamberg et al (2001). Since the OCTIGEN ELISA kit has been developed to measure the corticosterone concentration in serum and not in feces, it is uncertain to what extent the kit will quantify corticosterone metabolites present in feces.…”

“…To the best of our knowledge there are no groups who have attempted to establish assays allowing quantification of all peaks. Bamberg et al (2001) have developed antisera against relevant corticosterone metabolites but using an immunoassay based on an antibody against a corticosterone metabolite, albeit a major one, is not necessarily more biologically relevant than measuring corticosterone itself, perhaps including some cross-reacting metabolites that may react with the antiserum. It is perhaps important to emphasize that we experienced no difficulties measuring generous levels of immunoreactive corticosterone metabolites in rat feces and that the concentrations we recorded are in good agreement with the levels of fecal corticosterone (native molecular form only) measured using HPLC quantification (Guhad et al 2003).…”

“…saliva, tears, urine and feces). Fecal corticosteroids have been suggested useful in non-invasive assessment of preceding stress (4-12 h prior to feces sampling) in a number of species including cats and dogs , Schatz & Palme 2001, mice, deer mice and voles (Harper & Austad 2000, Touma et al 2003, rats (Bamberg et al 2001), roe deer (Dehnhard et al 2001), and non-human primates (Whitten et al 1998, Bahr et al 2000.…”

Marked for life? Effects of early cage‐cleaning frequency, delivery batch, and identification tail‐marking on rat anxiety profiles

“…Type II errors might be most likely in our baseline fecal corticosterone concentration, which had a noticeably wider confidence interval that the other measures: most differences in EH are found with stress-induced corticosterone responses, so basal differences are relatively subtle if they are observed at all (e.g., Macri et al, 2004;Plotsky & Meaney, 1993). Also, although the relative variation in fecal corticosterone concentrations is comparable to variation in plasma concentrations, it includes a longer timescale, with accompanying variation in rats' experience and circadian rhythm (Bamberg et al, 2001;Cavigelli et al, 2005). However, our power tests suggest that at least for plus maze and hyponeophagia data, we had more than a 98% chance of detecting an effect of the magnitude found between EH and NH rats (c.f.…”

“…Fecal pellets were collected from the human interaction test and the elevated plus-maze for baseline corticosterone analysis. This would give us a baseline measure, since although there is wide variance in the delay between serum and fecal corticosterone concentrations, serum levels are not reflected in the fecal boli until 16.7 AE 4.3 hr after a stressor (Bamberg, Palme, & Meingassner, 2001). The pellets were immediately placed into sealed 50 ml polypropylene tubes, and within a maximum of 2 hr, frozen at À20 C for up to 8 weeks before being sent for professional corticosterone assaying (Gordon Laboratory Group, Stockton-on-Tees, UK).…”