Sex differences in the excretion of fecal glucocorticoid metabolites in the Syrian hamster

Abstract

We verified the relevance of measuring fecal glucocorticoid metabolites (FGM) to assess the stress response of the Syrian hamster. Male and female hamsters (n = 10 each) were submitted to an adrenocorticotropic hormone (ACTH) challenge test, whereas animals in the control group received 0.5 mL of sterile isotonic saline solution. All feces voided by each animal were collected at 4 h intervals from 24 h before (baseline) until 48 h after injections. FGM were quantified using an 11-oxoetiocholanolone enzyme immunoassay (EIA). Basal concentrations of FGM were almost four times higher in males than in females. Following ACTH administration, FGM levels started rising from 8 h onwards, reaching peak concentrations 20 or 28 h post injection in males and females, respectively. Despite the much higher absolute concentrations present in males, the relative increase (500%) in response to the ACTH stimulation was similar in both sexes. Sex differences in FGM levels are in accordance with results reported by others regarding the hamster adrenal physiology. The comparison of the adrenocortical response of males and females to an ACTH challenge provided new information about the amplitude and the timing of such a response and the excretion of glucocorticoids in both sexes. We demonstrated for the first time in the Syrian hamster that adrenocortical activity can be monitored in fecal samples in a noninvasive way. Our study provides a humane, practical, and noninvasive alternative to blood removal and therefore a powerful tool for stress-related studies in a species frequently used as an animal model in medical research.

Excretion and measurement of corticosterone and testosterone metabolites in bank voles (Myodes glareolus)

“…Additional peaks (after 12-16 h) probably reflected an enterohepatic recirculation of some metabolites . A similar time lag has been observed in mice (Touma et al 2003), spiny mice (Acomys cahirinus; Nováková et al 2008) and even in red squirrels (Dantzer et al 2010) whereas in syrian hamster, member of the same family as bank voles, the gut passage time is 3 -4 times longer (Chelini et al 2010). This time indicates the average gut passage time of corticosterone metabolites in bank voles, which is a highly important piece of information when examining the endocrine status of animals based on excreta .…”

“…Opposite to mice (Touma et al 2003) the amounts of measured FCM were significantly higher in males than in females. A similar dimorphism has been observed in Syrian hamsters and common hamsters and is likely caused by the larger adrenal glands and greater steroid production in males (Huhman et al 2003, Franceschini et al 2007, Chelini et al 2010. However, sometimes the chosen EIA detects more FCM formed by one sex, which can cause sex differences in the results (Touma et al 2003).…”

“…For measuring fecal corticosterone metabolites (FCM) we used a 5α-pregnane-3β,11β,21-triol-20-one EIA, which measures steroid metabolites with 5α-3β,11β-diol structure and was first developed and validated for mice (Mus musculus f. domesticus) (Touma et al 2003, Touma et al 2004. It has been shown to be also suited for rabbits (Oryctolagus cuniculus; Monclús et al 2006), rats (Rattus norvegicus; Lepschy et al 2007), hamsters (Mesocricetus auratus;Chelini et al 2010) and several squirrel species (Bosson et al 2009, Dantzer et al 2010, Bosson et al 2013, Hammond et al 2015. For fecal testosterone metabolites (FTM) we used a testosterone EIA (measuring 17β-hydroxyandrogens) first described by Palme and Möstl (1994).…”

Resposta endócrina à contenção física e isolamento em papagaios-verdadeiros

“…Hunt 2005), galináceos (Rettenbacher et al 2004) e mamí-feros, como o hamster sírio (Chelini et al 2010), o presente estudo também não evidenciou diferenças significativas nas concentrações de MG entre machos e fêmeas de papagaios-verdadeiros. Essa resposta adrenocortical semelhante entre os sexos foi também observada por Ferreira et al (2015) quando avaliaram, fora da estação reprodutiva, as concentrações de metabólitos de glicocorticoides nas excretas de papagaio-verdadeiro ao longo do dia e após desafio com ACTH.…”

Validação de um radioimunoensaio para a quantificação de metabólitos fecais de testosterona em hamster Sírio (Mesocricetus auratus)

“…Estudos anteriores já mostraram que é possível monitorar a função ovariana da fêmea de hamster através da quantificação dos metabólitos fecais de estradiol e de progesterona (Chelini et al 2005), assim como a resposta adrenocortical ao estresse tanto de machos como de fê-meas analisando nas fezes os metabólitos de glicocorticóides (Chelini et al 2010). Entretanto, não foi possível encontrar na literatura nenhuma validação, para o hamster, da dosagem de metabólitos fecais de testosterona.…”