Research Group Stress

Stress

english version

Prof. Dr. E. Möstl, Prof. Dr. R. Palme, Dr. S. Rettenbacher, Dr. M. Lepschy, Mag. S.A. Omer, Dr. M. Stöwe, M. Höring, E. Klobetz-Rassam, S. Hartl, S. El-Makarem

Overview of our recent work

Non-invasive monitoring of glucocorticoid production

In animals under stress, glucocorticoids and catecholamines are secreted by the adrenals. These hormones help an organism to cope with the situation. Their concentrations in blood have been widely used to evaluate the effects of various stressors. Blood sample collection itself disturbs an animal and is dangerous or even impossible in some zoo and wildlife species. Non-invasive methods for the determination of glucocorticoids or their metabolites are therefore a prerequisite for assessing stress in these animals. Above all, faecal samples offer the advantage that they can be collected easily without any need to handle the animal.

As information about faecal metabolites was very limited, our special interest during the past several years has been steroid metabolism and excretion in mammals, mainly domestic livestock (Palme et al., 1996). Starting with these infusion experiments (in the meantime, we have added further studies in cats, dogs, hares, rats, mice, primates, elephants and several bird species; for review, see Palme et al., 2005), we have focused on faecal glucocorticoid metabolites. Since we were not able to find authentic cortisol in faecal samples of ruminants and horses and only negligible amounts in pigs, specific cortisol immunoassays do not work in these species. In sheep, we characterized 14C-cortisol metabolites by HPLC/MS. This helped to establish an enzyme immunoassay for 11,17-dioxoandrostanes (11-oxoaetiocholanolone-EIA) for a determination of faecal cortisol metabolites (Palme and Möstl, 1997). It was the first EIA worldwide to measure cortisol metabolites in ruminants. This EIA provided the basis for a non-invasive evaluation of adrenocortical activity. The biological relevance of this non-invasive method has been proven in ruminants (cattle, sheep) and horses following stimulation (ACTH) or suppression (dexamethasone) of cortisol release by the adrenal cortex and transportation. In the meantime, we have developed and established a total of more than 10 different EIAs for other faecal cortisol or corticosterone metabolites. The biological relevance of these EIAs for faecal glucocorticoid metabolites in various species (including birds; see ref.) has been proven (Möstl et al., 2005; Palme, 2005; Palme et al., 2005; Touma and Palme, 2005).

Thus, our successfully established and extensively validated non-invasive techniques to monitor stress hormone metabolites in faecal samples of various species are a useful tool in different research fields, such as ethology, field endocrinology, ecology, animal conservation and animal welfare, and can open new perspectives in biomedical and behavioral sciences.

 

 

Stress and foetal development

Steroid hormones, secreted by the mother, affect embryonic development. In birds, androgen content of the eggs is modified according to environmental conditions. This is believed to be an epigenetic tool to optimize reproductive success. However, an explanation for the underlying physiological mechanism is still lacking. Using hens’ eggs as an experimental model, our group is currently investigating a possible regulatory mechanism involving maternal glucocorticoids. This project was funded by a grant of the Austrian Science Foundation to S. Rettenbacher.

Catecholamine metabolism

In addition, we are currently investigating the metabolism and excretion of catecholamines and their adduct products in the blood of various animal species. This project is also funded by a grant of the Austrian Science Foundation (postdoc: Michael Lepschy).

Glucocorticoids in hair

As a potential long-time parameter of average glucocorticoid concentrations, the measurement of cortisol in hairs (corticosterone in feathers) has attracted much attention. As recent studies from others and our group (Keckeis et al., 2012) suggest also a local glucocorticoid production in the skin, we try to evaluate mechanisms of and possible influences on glucocorticoid (or their metabolites) production in skin appendages.

Corticosteroid binding globulin in birds

According to the free hormone hypothesis only unbound corticosterone is biologically active and responsible for the hormonal response to stress. Data of our group concerning cortisol measured in saliva support this hypothesis. Corticosteroid binding globulin (CBG) binds corticosteroids and thereby modulates the amount of free glucocorticoids in blood. In contrast to mammals, in birds all steroids bind to CBG (mammals additionally have sex steroid binding globulin) and compete for CBG binding sites. Up to date CBG concentrations in bird plasma are measured indirectly via equilibration dialysis. We are currently developing an enzyme immunoassay to directly measure CBG concentrations in bird blood. Once this method is established, we will focus on competition of steroids at CBG binding sites during early development and in response to (social) challenges (postdoc: Mareike Stöwe).

Glucocorticoid metabolites in the environment

Especially in ruminants high amounts of C19O3-steroids are excreted. Those metabolites can be measured as parameters of glucocorticoid production. However, some are known to act as pheromones and androgens in fish (11-ketotestosterone is an important androgen). We investigate formation and stability of these possible endocrine disruptors.

As we are interested in endocrine rhythms and responses to stress or disturbance, we are collaborating with research groups from all over the world (e.g., Australia, Argentina, Austria, Brazil, Belgium, Canada, Denmark, France, Germany, Great Britain, Italy, Netherlands, New Zealand, Norway, Poland, South Africa, Spain, Sweden, Switzerland, USA). We are also involved in animal welfare projects. Feel free to contact us if you are interested in a collaboration, in copies of papers (PDFs are available), or if you have further questions. We also offer basic information about non-invasive measurement of steroid hormones (including our detailed laboratory protocol for extraction and EIA and the PDFs of our papers) that is directly available on our website via the following link: http://wwwsrv.vu-wien.ac.at/i103/stress-cd/ [Link 1]

further keywords: feces, fecal, noninvasive

Stress

deutsche Version

Prof. Dr. E. Möstl, Prof. Dr. R. Palme, Dr. S. Rettenbacher, Dr. M. Lepschy, Dr. M. Stöwe, M. Höring, E. Klobetz-Rassam, S. Hartl, S. El-Makarem

Forschungen über Belastungen sind sowohl für das Wohlbefinden der Tiere, die Verhaltensforschung, im Bereich der Arterhaltung (conservation biology), der Landschaftsnutzung als auch im medizinischen Bereich von Bedeutung, da umfangreiche Kenntnisse wichtig sind, um Strategien zur Stressverminderung bzw. –vermeidung bei Tieren zu entwickeln. Der Organismus reagiert auf Belastungen mit einer vermehrten Ausschüttung von Hormonen ins Blut. Diese Hormone (Glukokortikoide bzw. Katecholamine) werden vom Körper verstoffwechselt und über Harn und Kot ausgeschieden. Die Messung solcher Metaboliten im Kot erlaubt die nicht-invasive Überwachung von Belastungen (Transport, Haltung, Schmerz), denen die Tiere ausgesetzt wurden und damit eine objektivere Bewertung.Die Arbeitsgruppe „Stress“ beschäftigt sich seit einiger Zeit mit der Charakterisierung dieser Abbauprodukte von Glukokortikoiden, wobei es gelang, weltweit erstmals ein Testsystem zur quantitativen Erfassung im Kot zu etablieren. Mittlerweile wurden mehrere solcher Testsysteme entwickelt und bei verschiedenen Tierarten (Säugetiere und Vögel) erfolgreich eingesetzt. Dies wird durch eine große Anzahl interdisziplinärer Kooperationen mit Gruppen im In- und Ausland (Veterinärmediziner, Ethologen, Biologen bzw. Biomediziner) dokumentiert.Derzeit arbeitet diese Gruppe, neben einer Verbesserung der bestehenden Methodik, überwiegend an der Aufklärung der Metabolisierung von Katecholaminen (Adrenalin, Noradrenalin) bzw. an den Auswirkungen von pränatalem Stress auf die sich entwickelnde Frucht.

 
 

letzte Änderung: 26.07.2012

 

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Öffnungszeiten

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Sekretariat (Beschaffung, Verwaltung):
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Kontakt

Institut für Medizinische Biochemie
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