Background: Subtle and inconsistent differences in hypothalamic-pituitary-adrenal (HPA) axis activity have been reported for patients with panic disorder. While these patients show little or no alterations in basal ACTH and cortisol levels, it has been hypothesized that HPA hyperresponsivity was a trait in panic patients when exposed to novel and uncontrollable stimulation. Methods: Thirty-four patients (23 females, mean age 35 yrs) diagnosed with panic disorder were compared to 34 healthy controls matched for age, gender, smoking status, and use of oral contraceptives. Both groups were exposed twice to a potent laboratory stress protocol, the Trier Social Stress Test (TSST) on consecutive days. Free salivary cortisol levels and heart rate responses were repeatedly measured before and following the TSST. In addition, the cortisol awakening response (CAR) was assessed to further investigate HPA reactivity in PD patients. Results: While the TSST induced similar heart rate stress responses in both groups, cortisol responses were clearly absent in the panic patients with normal responses in the controls (F(1.96, 66) = 20.16; p < 0.001). No differences in basal cortisol levels were observed in the extended baseline period. The same cortisol stress non-response patterns were observed when patients with/without comorbid depression, or with/without psychotropic medication were compared. In contrast to their non-response to the psychosocial stressor, panic patients showed a significant CAR. Conclusion: These findings provide strong evidence to suggest that PD patients present with a striking lack of cortisol responsivity to acute uncontrollable psychosocial stress under laboratory conditions. This unresponsiveness of the HPA axis appears to be rather specific, since a normal CAR in the morning could be documented in these patients. Thus, the present results do not support the hypothesis that PD patients show a trait HPA hyperresponsiveness to novel and uncontrollable stimulation. In contrast, the data provide support for a hyporesponsive HPA axis under emotional stress in PD patients.

Mit dieser Arbeit sollte erforscht werden, welchen Einfluss Umsetzung und Vergesellschaftung von Grevy- bzw. Böhm-Zebras in Zoologischen Gärten auf die Produktion von Stressund Sexualhormonen haben. Dafür wurden vor, während und nach dem Umsetzungs- und Vergesellschaftungsprozess Kotproben der Zebras gesammelt,bei -20°C gelagert, mit einem Methanol-Wasser-Gemisch extrahiert und anschließend deren Gehalt an Cortisol-, Progesteron-, Östradiol- und Testosteronmetaboliten analysiert. Dabei konnte gezeigt werden, dass sowohl bei den adulten Grevy-Zebrastuten als auch bei deren Jungtieren (Zoo Leipzig) im Untersuchungszeitraum 2004 das ranghöchste und rangniedrigste Tier, 2008 nur das dominante Tier die höchsten Cortisolspiegel der Gruppe aufwiesen. Das in der Rangordnung den mittleren Platz einnehmende Zebra zeigte signifikant niedrigere Cortisolspiegel. Von den drei untersuchten Böhm-Zebras (Zoo Halle) besaß der Hengst signifikant niedrigere Cortisolwerte als die beiden Stuten, deren Cortisolspiegel sich vor der Umsetzung nicht signifikant voneinander unterschieden. Die Umsetzung der Grevy- Zebras in die Kiwara-Savanne und die Vergesellschaftungen mit Säbelantilopen, Straußen und Giraffen und auch die Umsetzung der Böhm-Zebras in ihr neues Gehege erhöhten jedoch nur bei den subdominanten Tieren den Basiswert des Cortisols signifikant. Zusätzliche Faktoren, wie z. B. sozialer Status (dominant vs. subdominant), soziale Ordnung und weitere exogene Einflüsse scheinen somit eine entscheidende Rolle bei der Stress-Verarbeitung von in Zoologischen Gärten gehaltenen Zebras einzunehmen. Die Adaptation der Zebras an ihre neue Umgebung nahm in den beiden Zoos unterschiedliche Zeitspannen in Anspruch. Bei den Grevy-Zebras war es aus tiergärtnerischen Gründen nicht möglich, diese AdaptationsZusammenfassung zeit zu definieren, da nur bis zwei Monate nach der Umsetzung eine individuelle Kotprobensammlung erfolgte und zu dieser noch bei einzelnen Tieren erhöhte Cortisolwerte messbar waren. 2008 konnten jedoch bei den adulten Stuten signifikant niedrigere Cortisolspiegel gemessen werden als 2004 im alten Gehege. Bei den drei untersuchten Steppenzebras fielen ca. vier Wochen nach der Umsetzung die Cortisolkonzentrationen deutlich ab und waren bei den beiden Stuten signifikant niedriger als im alten Gehege und als in der Zeit direkt nach der Umsetzung. Dies lässt die Schlussfolgerung zu, dass die neuen Gehege günstigere Umweltbedingungen bieten als die alten Zebra-Anlagen. Bei der Auswertung der Sexualhormone wurde deutlich, dass alle drei Grevy-Zebrastuten im nicht tragenden Zustand sehr ähnliche Sexualhormonspiegel zeigten. Nach der Umsetzung war weder für Progesteron noch für Östradiol ein charakteristischer Zyklusverlauf zu erkennen. Es ist also anzunehmen, dass hier der durch die Umsetzung und Vergesellschaftung hervorgerufene Stress und damit das Ansteigen der Cortisolproduktion einen negativen Einfluss auf die Reproduktionsfähigkeit der untersuchten Zebras hatte. Die Böhm-Zebras waren während der Umsetzung tragend. Die Narkose und die neue Umgebung hatten keinen messbaren Einfluss auf die Sexualhormone und am Ende einer physiologischen Tragezeit wurden zwei gesunde Jungtiere geboren. Bei den beiden Böhm-Zebrastuten konnten des Weiteren die Östradiol- und Progesteronexkretionsprofile über drei Jahre hinweg aufgenommen und somit die Trächtigkeitsdauer und der Hormonverlauf während der Trächtigkeit beschrieben werden. Das Hormonprofil des Östradiol gleicht weitestgehend dem bei Grevy- Zebras geschilderten Verlauf mit der maximalen Ausscheidung während des zweiten Trimesters. Die Konzentration der Progesteronmetabolite weicht jedoch deutlich von dem bei Grevy- Zebras beschriebenen Profil ab. Hier konnte ein stetiges Ansteigen der Werte ermittelt werden, wobei frühestens ab der 8. Woche a.p. Werte über 200ng/g erreicht wurden und die höchsten Konzentrationen ca. 12 bis einen Tag a.p. bzw. einen Tag post partum gemessen wurden. Die durchschnittliche Trächtigkeitsdauer betrug 343±15 Tage. Mit dieser Arbeit konnte gezeigt werden, dass mittels Hormonbestimmungen im Kot von Zebras Veränderungen im Hormonhaushalt sowohl von Stress- als auch von Sexualhormonen sehr gut quantifiziert werden können. Dadurch besteht die Möglichkeit, den Einfluss tiergärtnerisch wichtiger Verfahren, wie das Umsetzen und Vergesellschaften von Zebras oder die Kontrolle von Trächtigkeiten wissenschaftlich auszuwerten und Aussagen über die Qualität der Haltungsbedingungen zu treffen. Des Weiteren können über die individuellen Cortisolmetabolitkonzentrationen Rückschlüsse auf die soziale Stellung innerhalb der Gruppe gezogen und die Auswirkungen dieser auf den Umgang mit „Stress“ charakterisiert werden.

No description available.

Objectives: Patients with Panic Disorder (PD) show an abnormal stress-induced functioning of the Hypothalamic-Pituitary-adrenal (HPA)-axis. Different protocols for stress induction are of rather low relevance for the psychotherapeutic treatment. In practice, interoceptive exposure is often realized as Low Intensity Exercise (LIE), as compared to an incremental cycle exercise test to exhaustion. Currently, it is not known, whether LIE displays an effective interoceptive stressor 1.) leading to a significant anxiety induction; 2.) a comparable HPA- and Sympathetic-Adreno-Medullar (SAM)-axis response in both patients and healthy controls; 3.) stress responses under LIE are associated with treatment outcomes. Patients and methods: N = 20 patients with PD and n = 20 healthy controls were exposed to ten minutes of LIE on an exercise bike. LIE was applied as part of the interoceptive exposure, during an intensive Cognitive-Behavioral Therapy (CBT) in a day clinic. Heart rate was monitored and salivary cortisol samples collected. Before and after the LIE, state anxiety/ arousal were assessed. In order to evaluate psychopathology, the Panic and Agoraphobia Scale, Mobility Inventory, Agoraphobic Cognitions Questionnaire and Body Sensations Questionnaire were applied, before (T1) and after five weeks (T2) of an intensive CBT. Results: LIE led to a significant and similar heart rate increase in both groups. Cortisol decreased over time in both groups, especially in male patients. A higher psychopathology before, and after CBT, was associated with a significantly lower cortisol response under LIE. Conclusions: In the present study, LIE led to a divergent stress response: while there was a significant heart rate increase, cortisol decreased over time, particularly in male patients. A lower reactivity of the HPA-axis seems to be associated with a lower treatment outcome, which may affect extinction based learning. The findings suggest, that interoceptive stimuli should be designed carefully in order to be potent stressors.

Master of Science / Department of Clinical Sciences / James W. Carpenter / In many species, temporary increases in glucocorticoids (GC) can be used to identify changes in adrenal activity in response to acute stressors. For this research, GC metabolites were identified in fecal extracts from various Atelopus species. The objectives were to identify possible correlates between GCs and health status, assess the impact of husbandry protocols on adrenal activity, and evaluate the sub-lethal effects of antifungal bacteria used for protection of frogs against the chytrid fungus (Batrachochytrium dendrobatidis; Bd). The first study examined whether fecal GC concentrations can be correlated with animal health and behavior changes in a captive setting. Atelopus zeteki with varying degrees of dermatitis were categorized based on the severity of their skin abnormalities and GC metabolite concentrations were analyzed to detect correlations between severity of disease and GC metabolite concentrations. Similarly, behaviors that may indicate elevated stress levels (e.g., time spent in hide) were analyzed to detect correlation between disease and behavior changes. There was no correlation between fecal GC metabolites and health status of the animal or between health status and amount of time spent in hide. The second study established ex situ colonies of two Panamanian frog species, Atelopus certus and Atelopus glyphus, to determine how male group size affects behavior and GC levels. When housed in groups of eight, animals initially had elevated GC concentrations and interacted aggressively, but these instances declined substantially in the first 2 weeks of being housed together. Thus, captive Atelopus populations can be housed in same-sex enclosures without causing sub-lethal stress on the individuals involved. The third study examined the ability of antifungal bacterium from Central America to propagate on Atelopus skin as a preventative treatment for Bd and the sub-lethal effects of each bacteria species on adrenal function based on GC analysis. Four species of bacteria (Pseudomonas sp., Pseudomonas putida, Chryseobacterium indolgenes, and Stenotrophomonas maltophili) were found to be successful Bd inhibitors in vitro. There were no detectable effects of bacterial exposure with GC metabolite concentrations over time for any of the treatments assessed.

Intra-adipose cortisol is derived from the systemic circulation via the hypothalamic-pituitaryadrenal axis (HPAA) and generated locally through conversion of inactive cortisone to cortisol by the intra-cellular enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1). This thesis addresses the relative contributions of the HPAA and adipose tissue 11βHSD1 to the adipose tissue glucocorticoid pool and describes development and validation of a novel stable isotope tracer, 1,2 [2H]2-cortisone (d2-cortisone), to measure 11βHSD1- dehydrogenase activity in adipose tissue and skeletal muscle in vivo. In otherwise healthy females (n=6) undergoing hysterectomy for a benign indication, an intravenous infusion of d4-cortisol was administered and subcutaneous and omental adipose tissue biopsies were obtained along with concomitant peripheral venous blood, to measure the rate of exchange of cortisol between plasma and adipose tissue for comparison with rates of intra-cellular cortisol generation by 11βHSD1. Cortisol concentrations and enrichment with d4-cortisol were lower in adipose tissue than in plasma. The rate of accumulation of d4-cortisol in adipose tissue depots was ~0.5nmol/kg/h despite the infusion contributing 1.9μmol/h d4-cortisol into the circulation, and the proportion of the intra-adipose cortisol pool replaced each hour was ~10%. The contribution of 11βHSD1 to this turnover could not be quantified since very little substrate d3-cortisone accumulated in adipose during infusion. Method development for d2-cortisone included optimising LC-MS/MS conditions, confirming that d2-cortisone was a substrate for human 11βHSD1 and that no significant primary isotope effect existed. The pharmacokinetics of d2-cortisone were assessed in vivo in healthy male volunteers (n=3). The method was validated by measuring whole body cortisone production in healthy volunteers (n=3) before and after eating liquorice which resulted in a ~50% fall in cortisone production. 11βHSD1-dehydrogenase activity was measured in adipose tissue and skeletal muscle in healthy volunteers (n=6) using d2- cortisone and substantial 11β-dehydrogenase activity was present in both tissues (~1.5-fold higher 11β-dehydrogenase activity than 11β-reductase activity in adipose tissue and approximately equal 11β-reductase and 11β-dehydrogenase activity in skeletal muscle). 11βHSD1-reductase activity was also assessed using a 9,11,12,12 [2H]4-cortisol infusion (d4-cortisol). Skeletal muscle and adipose tissue displayed 11β-reductase activity. In adipose tissue this activity was of a similar magnitude to previous reports. Insulin increased whole body 11β-reductase activity, but did not switch 11βHSD1 direction in muscle or adipose tissue, indicating the predominant effect of insulin may be on hepatic 11βHSD1. Therefore, turnover of the intra-adipose tissue glucocorticoid pool is slow and it is unlikely that rapid acute fluctuations in circulating cortisol are reflected in adipose tissue, although this has not been confirmed under normal physiological conditions. Secondly, 11βHSD1 may be bidirectional in human subcutaneous adipose tissue and skeletal muscle in vivo, and insulin does not regulate the balance of activities. However, in this study blood sampling occurred from blood vessels which express 11βHSD2, and thus some of the measured dehydrogenase activity in this study may reflect endothelial 11βHSD2 activity. Together these findings further our understanding of adipose tissue cortisol physiology in health, suggesting that 11βHSD1 may play a relatively important role in modulating activation of glucocorticoid receptors in adipose tissue, and that dysregulation or inhibition of 11βHSD1 may affect cortisol inactivation as well as regeneration.

Cognitive impairment in coronary artery disease (CAD) patients can predict poorer quality of life, dementia, and increased mortality. This study aimed to determine the association between long-term cortisol elevations and cognitive function in CAD patients. Participants were recruited at the beginning of a 1 year cardiac rehabilitation program and followed forward. Composite Z-scores were computed from tests measuring memory and executive function at baseline and 1 year. Cortisol deposition (3 months) was measured from a 20 mg, 3 cm hair sample. Analyses of covariance showed less improvement in memory function (F1,50=4.721, p=0.035) but not executive function (F1,49=0.318, p=0.575) in patients dichotomized into a high cortisol group based on a previously established reference range. Prolonged cortisol elevation may be associated with cognitive changes in subjects with CAD.

Cognitive impairment in coronary artery disease (CAD) patients can predict poorer quality of life, dementia, and increased mortality. This study aimed to determine the association between long-term cortisol elevations and cognitive function in CAD patients. Participants were recruited at the beginning of a 1 year cardiac rehabilitation program and followed forward. Composite Z-scores were computed from tests measuring memory and executive function at baseline and 1 year. Cortisol deposition (3 months) was measured from a 20 mg, 3 cm hair sample. Analyses of covariance showed less improvement in memory function (F1,50=4.721, p=0.035) but not executive function (F1,49=0.318, p=0.575) in patients dichotomized into a high cortisol group based on a previously established reference range. Prolonged cortisol elevation may be associated with cognitive changes in subjects with CAD.

The Hypothalamus-Pituitary-Adrenal axis (HPA-axis) with its end product cortisol mediates the physiological response to stress thereby promoting mobilization of energy. The cortisol levels follow a diurnal rhythm with a distinct awakening response. Regulation of the HPA-axis differs among persons with certain psychiatric disorders when compared with controls. Some reports concern Attention-Deficit/Hyperactivity Disorder (ADHD) but findings are inconclusive. The main aim of the present thesis was to investigate diurnal levels of saliva cortisol in school aged children with ADHD and age matched non-affected comparisons, also taking early adversity, perceived stress and ADHD-medication into consideration. Children with ADHD had lower cortisol levels at awakening, 30 minutes later and before going to bed than comparisons. When the study group was split into three different age groups similar results were found only for children above 10 years of age. Within the ADHD group, subtype of ADHD or co-occurring symptoms did not affect the cortisol levels. Furthermore, children in the ADHD group had to a higher degree been exposed to foetal and childhood psychosocial adversity than comparisons. Since exposure to early adversity has been associated with both ADHD and HPA-axis functioning, such exposures could theoretically explain the low cortisol levels in ADHD via early programming of the HPA-axis. However, no relation was found between exposures to psychosocial adversity and diurnal cortisol levels. Neither did continuous medication with stimulants or atomoxetine explain the low cortisol levels. Possibly, medication may rather increase the levels. Finally, children with ADHD scored higher on perceived stress, measured by the Pressure-Activation-Stress (PAS) scale, than the comparison group. Female sex was also associated with higher stress in both groups, as well as increasing age in the comparison group. As with psychosocial adversity, no association was found between the higher PAS-scores and the lower cortisol levels, indicating the complexity of the stress regulating system. The results indicate a down-regulated or displaced HPA-axis with lower cortisol levels in children with ADHD. Stress related fragility – with more exposure to early stressors, higher perceived stress and lower diurnal cortisol levels – seem to accompany ADHD during childhood.

The depression of immune cell function that is typically observed after prolonged exercise is thought to be largely mediated by increased plasma concentrations of stress hormones and cytokines and possibly oxidative stress. The aims of this thesis were to determine the effects of acute and longer term oral antioxidant supplementation on immunoendocrine responses following prolonged exercise. In study 1 (Chapter 3) it was shown that vitamin C ingested acutely before and during prolonged exercise has little or no effect on immunoendocrine responses. Furthermore, the combined ingestion of vitamin C with carbohydrate provides no additional effects compared with carbohydrate alone. However, when vitamin C was supplemented acutely, 2 h prior to, and during prolonged exercise in addition to on the night before (14 h prior) exercise this limited the fall in neutrophil oxidative burst activity (study 2, Chapter 4). This was probably a result of reduced direct oxidative damage to neutrophils with vitamin C supplementation since there were no effects on the cortisol, interleukin-6, leukocytosis or neutrophilia responses. Longer periods of antioxidant supplementation (2 - 4 weeks) may be effective at blunting the cortisol, leukocytosis and neutrophilia responses to prolonged exercise (Chapters 5 and 6) but this had no effect on in vitro measures of neutrophil function. In study 5 (Chapter 7) it was shown that acute pre-exercise dark chocolate (which contains polyphenols) ingestion has some effects on plasma oxidative stress markers and circulating insulin and glucose responses but not the immunoendocrine responses to prolonged exercise.