Familial risk and environmental stress promote the development of alcohol dependence. We investigated whether a positive family history of alcoholism affects the neuroendocrine response to a standardized laboratory stress test in healthy subjects without alcohol use disorders. Twenty-four high-risk subjects with a paternal history of alcoholism (PHA) and 16 family history negative (FHN) controls were evaluated. Psychosocial stress was induced by having subjects deliver a 5-min speech and mental arithmetics in front of an audience on separate days, after drinking either placebo or ethanol (0.6 g/kg) in a randomized sequence. Adrenocorticotropin (ACTH) was measured in 10 plasma samples covering up to 75 min after the stress test. Plasma arginine vasopressin (AVP) was determined before the stressor, at the time of maximum ACTH secretion, and at 75 min after stress onset. The stress test induced a phasic increase in ACTH secretion. At the time of maximum ACTH, AVP was significantly increased in relation to baseline. Compared to placebo, alcohol administration significantly attenuated maximum ACTH concentration in PHA but not FHN subjects, and decreased AVP measured in the same samples in PHA but not FHN subjects. We conclude that activation of the hypothalamic–pituitary–adrenal system by psychosocial stress is accompanied by an increase in peripheral plasma AVP levels. Secretion of both ACTH and AVP suggest that alcohol attenuates the stress response selectively in PHA but not FHN subjects. This might imply some short-term positive alcohol effect in sons of alcoholics, but also constitute a mechanism by which their risk to develop alcohol use disorders is increased.

Objective: Description of the clinical, biochemical and genetic features of a Polish patient with familial glucocorticoid deficiency. Methods: Detailed clinical investigation, hormonal analysis and sequencing of the coding region of the melanocortin 2 receptor (MC2R) gene in this patient. Results: We report on a 3-month-old boy with familial glucocorticoid deficiency who presented at the age of 3 months with skin hyperpigmentation, muscle weakness, mild jaundice and constipation. Hormonal analyses revealed high ACTH and TSH serum concentrations, low serum cortisol concentration along with normal blood electrolytes. On hydrocortisone supplementation, the disease symptoms disappeared and the child recovered completely. His physical and mental development progresses normally. Genetic analysis disclosed a novel compound heterozygous MC2R mutation p.Leu46fs and p.Val49Met. Conclusion: The heterozygous p.Leu46fs mutation adds to the small number of MC2R nonsense mutations and is the first frameshift mutation within the first transmembrane domain of the receptor. According to molecular modeling the Val49Met mutation results in a structural change of the first transmembrane domain and in a potential novel interaction of the transmembrane domains I and VII. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Dans la majorité des cas, l’hypersécrétion de cortisol résulte d’un adénome hypophysaire sécrétant de l’ACTH (maladie de Cushing). Plus rarement, le syndrome de Cushing est la conséquence d’un adénome corticosurrénalien unilatéral ou d’une hyperplasie bilatérale des surrénales (HMBS) sécrétant du cortisol. Ces deux pathologies appartiennent à la catégorie des hypercortisolismes dits ACTH-indépendants en raison des taux plasmatiques effondrés d’adrénocorticotrophine (ACTH). Les mécanismes moléculaires à l’origine de la sécrétion accrue de cortisol par ces lésions sont longtemps restés méconnus. Au cours des dernières années, des avancées considérables ont été réalisées dans la compréhension des mécanismes moléculaires impliqués dans la physiopathologie du syndrome de Cushing. Deux grands types d’anomalies paraissent impliqués dans la pathogénie de l’hypercortisolisme : des mutations germinales et somatiques activant des voies de signalisation intracellulaires et l’expression illégitime de récepteurs membranaires. Dans la surrénale humaine normale, la sérotonine (5-HT), synthétisée et libérée par les mastocytes sous-capsulaires, stimule la sécrétion des corticostéroïdes via son récepteur 5-HT4. Ce dernier est principalement localisé à la surface des cellules de la zone glomérulée mais faiblement exprimé au niveau des cellules de la zone fasciculée, expliquant l’action stimulante prédominante de la 5-HT sur la sécrétion d’aldostérone. Dans la dysplasie micronodulaire pigmentée des surrénales, l’activation de la voie AMPc/PKA par une mutation du gène PRKAR1A est responsable d’une surexpression de la tryptophane hydroxylase (TPH) de type 2, enzyme limitante de la synthèse de 5-HT, et des récepteurs sérotoninergiques 5-HT4, 5-HT6 et 5-HT7 couplés positivement à la voie AMPc/PKA dans les cellules cortisolosécrétrices. Chez l’Homme, la sécrétion de cortisol est physiologiquement stimulée par l’ACTH également via la voie AMPc/PKA. Les patients souffrant de maladie de Cushing, d’un syndrome de Cushing paranéoplasique (paraCS), d’un déficit en 21-hydroxylase ou d’HMBS présentent des taux d’ACTH plasmatique ou intrasurrénalienne élevés. Chez ces patients, nous montrons que la stimulation chronique de la voie AMPc/PKA par l’ACTH provoque une surexpression de la TPH de type 1, du récepteur eutopique 5-HT4 et des récepteurs ectopiques 5-HT6 et 5-HT7 dans les cellules stéroïdogènes. Pour l’un des patients avec paraCS, nous avons pu montrer que les cellules corticosurrénaliennes en culture sécrètent du cortisol en réponse à la 5-HT ou à des agonistes des récepteurs 5-HT4 ou 5-HT7. Par ailleurs, le rôle de la voie Wnt/-caténine dans l’apparition des récepteurs illégitimes reste controversé. Nous avons donc évalué l’expression des récepteurs 5-HT4, 5-HT6, 5-HT7, du LH-R et du GIP-R dans une tumeur corticosurrénalienne avec mutation germinale du gène APC et deux modèles d’activation constitutive de la voie Wnt/-caténine dans le cortex surrénalien, incluant des souris génétiquement modifiées et des cellules corticosurrénaliennes humaines en culture primaire. Nos résultats indiquent que l’activation de la voie Wnt/-caténine favorise une surexpression significative du LH-R dans les 3 modèles étudiés. Globalement, les données issues de notre travail montrent que l’activation de voies de signalisation intracellulaire, comme la voie AMPc/PKA par l’ACTH ou la voie Wnt/-caténine par des mutations génétiques, favorise l’émergence de systèmes de régulation surrénaliens aberrants. Ils indiquent en outre que la 5-HT intrasurrénalienne est impliquée dans l’hypersécrétion de corticostéroïdes associée à différentes pathologies incluant la maladie de Cushing et le syndrome de Cushing paranéoplasique, le bloc en 21-hydroxylase et l’HMBS. Le recours à des inhibiteurs sélectifs de la tryptophane hydroxylase pourrait donc permettre de réduire l’excès de stéroïdes chez les patients atteints de ces affections. / In most cases, cortisol hypersecretion (Cushing’s syndrome; CS) results from ACTH-producing pituitary adenoma (Cushing’s disease). Occasionally, CS is the consequence of a unilateral adrenal adenoma or a bilateral macronodular adrenal hyperplasia (BMAH) producing cortisol. In these conditions, hypercortisolism is referred to as “ACTH-independent” owing to suppressed plasma ACTH levels. The molecular mechanisms underlying the maintenance of cortisol hypersecretion by adrenocortical adenomas and BMAHs in the absence of circulating ACTH has long remained unknown. However, major advances have been made during the past recent years in the comprehension of the pathophysiology of primary adrenal CS. Two main types of molecular defects have been shown to favor cortisol hypersecretion by adrenocortical neoplasms: somatic mutations responsible for activation of intracellular signaling pathways and abnormally expressed (or illegitimate) membrane receptors by tumor cells. In the human adrenal gland, serotonin (5-HT), released by subcapsular mast cells stimulates corticosteroid secretion through activation of its type 4 receptor (5-HT4R). The 5-HT4R is principally expressed in zona glomerulosa cells but weakly expressed in zona fasciculata cells explaining why 5-HT strongly stimulates aldosterone production. Interestingly, in primary pigmented nodular adrenocortical disease (PPNAD) cells, activation of the cAMP/PKA pathway by PRKAR1A mutations triggers upregulation of the 5-HT synthesizing enzyme tryptophan hydroxylase (TPH) type 2 together with the 5-HT4, 5-HT6 and 5-HT7 receptors, positively coupled to cAMP/PKA signaling pathway. 5-HT strongly stimulates cortisol production and inhibition of TPH reduced corticosteroidogenesis in cultured PPNAD cells. In human, cortisol secretion is normally stimulated by ACTH also through activation of the cAMP/PKA signaling pathway. Patients suffering from Cushing’s disease, paraneoplastic Cushing’s syndrome (paraCS), 21-hydroxylase deficiency or BMAH display high plasma or intraadrenal ACTH levels. In these patients, we show that chronic stimulation of cAMP/PKA pathway by ACTH induces TPH type 1 and 5-HT4/6/7 receptors overexpression in steroidogenic cells. In primary cultured adrenocortical cells originating from a patient with paraCS, 5-HT and 5-HT4/7 receptors agonists were able to activate cortisol secretion. On the other hand, the role of Wnt/-catenin signaling pathway in the emergence of illegitimate receptors is still debated. We therefore evaluated 5-HT4, 5-HT6, 5-HT7, LH/hCG and GIP receptors expression in an adrenocortical tumor with APC germline mutation and two experimental models of constitutive activation of β-catenin in adrenocortical cells, namely genetically modified mice and human transfected adrenocortical cells. Our results indicate that Wnt/-catenin pathway activation promotes significant overexpression of LH/hCG receptor in the 3 models investigated. Globally, our data show that activation of intracellular signaling pathways such as the cAMP/PKA pathway by ACTH or Wnt/-catenin by genetic mutations favors the emergence of abnormal regulatory systems in the adrenal cortex. Our results also demonstrate that intraadrenal 5-HT is involved in corticosteroids hypersecretion related to different diseases including Cushing’s disease, paraneoplastic Cushing’s syndrome, 21-hydroxylase deficiency and BMAH. TPH inhibitors may thus represent a new therapeutic approach of corticosteroid excess in patients suffering from these disorders.

Nutztiere sind aufgrund ihrer Haltungsbedingungen diversen Stressoren ausgesetzt, welche ihre physische und psychische Gesundheit beeinträchtigen können. Im Rahmen von Animal Welfare Monitoring besteht daher ein großes Interesse an der Entwicklung und dem Einsatz minimal-invasiver Methoden und tierbezogener Belastungsindikatoren. Haarcortisol-konzentrationen (HCCs) könnten hierfür ein vielversprechender, retrospektiver Stressindikator sein, da sie die durchschnittlichen systemischen Cortisolkonzentrationen der letzten Wochen bis Monate in nur einer Probe widerspiegeln. Bevor HCCs jedoch als zuverlässiger Indikator eingesetzt werden können, müssen potenzielle Einflussfaktoren darauf ermittelt werden. Das generelle Ziel der vorliegenden Arbeit ist die Untersuchung von Einflussfaktoren auf Haarcortisol und seine Eignung für die Beurteilung von Langzeitstress bei Rindern und Schweinen. Daher zielten die vorliegenden Studien darauf ab, (1) Wissenslücken in der Forschung zu identifizieren, (2) die Wirkung potenzieller Einfluss- und Störfaktoren zu evaluieren und (3) zu untersuchen, ob und wann erhöhte systemische Cortisollevel durch HCCs nachweisbar sind. Alle Haarproben wurde von Holstein-Rindern, Landrasse- und Sattelschweinen bzw. Kreuzungstieren entnommen. Aufgrund der Literaturrecherche (Studie 1) wurden potenzielle Einflussfaktoren identifiziert und in den nachfolgenden Studien untersucht. Für die Evaluierung nicht-stressbedingter Faktoren (Studie 2), wurden insgesamt 614 Tiere verwendet. Hierfür wurden Haarproben in verschiedenen Altersstufen (Neugeborene bis Erwachsene), von beiden Geschlechtern und während der Sommer- und Wintersaison entnommen. Außerdem wurden schwarze und weiße Haarproben, unterschiedliche Körperregionen (Nacken/Schulter, Rücken, Schwanzspitze) und verschiedene Haarsegmente untersucht. Der Einfluss von Kontaminationen auf HCCs wurde in einer in-vitro-Studie (Studie 4) mit Haarproben von 12 Kühen und 12 Sauen evaluiert. Diese Proben wurden für vier Wochen täglich mit Urin, Speichel, Kot oder Wasser behandelt oder blieben unbehandelt. Um die Wirkung von Langzeitstress auf HCCs zu untersuchen (Studie 3), wurde bei 34 Rindern und 38 Jungsauen über vier Wochen jeden zweiten Tag ACTH- oder Kochsalzlösung appliziert. Vor, sowie zu drei Zeitpunkten nach Ende der Behandlung, wurden native und neu gewachsene Haare sowie zusätzlich Haarsegmente entnommen. Alle Haarproben wurden zweimal mit Isopropanol gewaschen, mit einer Kugelmühle gemahlen und Cortisol nach Extraktion mit Methanol mittels ELISA nachgewiesen. Die statistische Auswertung erfolgte mittels SAS/STAT-Software unter Anwendung von ANOVA und paarweisen Vergleichen durch Tukey-Kramer Tests. Die Ergebnisse der Studie 2 zeigen signifikant höhere HCCs bei neugeborenen Kälbern im Vergleich zu Jungrindern, Färsen und Kühen (p < 0,001). Ebenso wiesen 2 Wochen alte Ferkel höhere HCCs auf als Schweine im Alter von 10 oder 27 Wochen oder Sauen (p < 0,001). Das Geschlecht hatte keinen Einfluss auf die HCCs beider Tierarten. Jedoch waren bei beiden Spezies die HCCs in Schwanzhaaren, im Vergleich zu den Schulter-, Nacken- und Rückenhaaren signifikant erhöht (p < 0,001), ebenso in schwarzen Haaren im Vergleich zu weißen Haaren (p < 0,05) und in distalen im Vergleich zu proximalen Haarsegmenten (p < 0,001). Außerdem wiesen Rinder im Winter höhere HCCs als im Sommer auf (p < 0,001). Die Ergebnisse der Studie 4 zeigen, dass die Kontamination mit Urin bei beiden Spezies eine konzentrationsabhängige Zunahme der HCCs bewirkt. Auch die Kontamination mit Speichel und Kot erhöhte die HCCs, jedoch nur bei Rindern (alle p < 0,05). Die Behandlung mit Wasser führte zu einer Auswaschung von Cortisol aus Haaren vom Schwein, jedoch nicht vom Rind. Die Ergebnisse der ACTH-Studie (Studie 3) zeigen signifikant erhöhte HCCs bei ACTH-Tieren zum Ende der Behandlung in nativen Haaren (p < 0,001), nachgewachsenen Haaren (p < 0,01) und in Haarsegmenten (p < 0,05). Die höchsten HCCs wurden innerhalb von vier Wochen nach Behandlungsende gefunden. Bei Schweinen wurde ein Anstieg der HCCs sowohl in ACTH- als auch in Kontrolltieren beobachtet ohne dass Unterschiede zwischen den Behandlungen auftraten. Die Ergebnisse zeigen, dass die Cortisolkonzentrationen im Haar bei Schweinen und Rindern durch Alter, Körperregion, Haarfarbe, Haarsegment und Jahreszeit beeinflusst werden. Es gibt erste Belege, dass die Kontamination von Schweine- und Rinderhaaren mit cortisolhaltigen Körperflüssigkeiten, wie Urin und Speichel, die Aufnahme von externem Cortisol in den Haarschaft verursacht. Bei der Verwendung von HCC als Stressindikator sollten daher diese Einflussfaktoren standardisiert und Kontaminationseffekte vermieden werden, z.B. durch die Verwendung von Aufwuchsproben oder nur proximaler Haarsegmente. Darüber hinaus konnte gezeigt werden, dass Langzeitstress durch wiederholte Aktivierung der HPA-Achse zu erhöhten Cortisolkonzentrationen im Haar führt. Bei Rindern zeigt sich dies in den HCCs verschiedener Haarprobentypen. Insgesamt erweist sich die Analyse von Cortisol im Haar als eine geeignete Methode zum Nachweis von Langzeitstress bei Rindern und Schweinen und könnte daher eine wichtige Komponente bei der Beurteilung von Animal Welfare sein.:1 General introduction 2 Review of the literature 2.1 The relevance of stress assessment in animal welfare 2.2 Stress response in mammals 2.2.1 Structure and function of the hypothalamic-pituitary-adrenal axis 2.2.2 Characteristics and effects of cortisol 2.2.3 Conventional biological matrices for cortisol analysis 2.3 Hair as a matrix for cortisol analysis 2.3.1 Hair structure and hair types 2.3.2 Hair growth cycle 2.3.3 Incorporation of cortisol into the hair 2.3.3.1 Passive diffusion 2.3.3.2 Multi-compartment model 2.3.4 Elimination of cortisol from the hair 2.3.5 Specific characteristics and applications of hair cortisol 3 Research focuses and aims 4 Results 4.1 Study 1: Hair cortisol for the assessment of stress (review) 4.2 Study 2: Effects of animal-based, seasonal and hair-specific factors on hair cortisol concentrations 4.3 Study 3: Effects of long-term stress on hair cortisol concentrations 4.4 Study 4: Effects of contamination and elimination on hair cortisol concentrations 5 General discussion 5.1 Influencing factors on hair cortisol concentrations in cattle and pigs 5.1.1 Impact of animal-based, seasonal and hair-specific factors 5.1.2 Impact of contamination and elimination by washout 5.1.3 Implications 5.2 Hair cortisol concentration as an indicator of long-term stress in cattle and pigs 5.2.1 Model for the increased release of systemic cortisol 5.2.2 Models for the time course of cortisol incorporation into the hair shaft 5.2.3 Impact of hair sample type and sampling time 5.2.4 Implications Table of contents 5.3 Future perspectives 5.4 Conclusions 6 Summary 7 Zusammenfassung 8 References 9 Danksagung / Farm animals can be exposed to various stressors due to their husbandry conditions, which can impair their health and welfare. Thus, there is interest in the use of minimally invasive methods and animal-based stress indicators as part of welfare assessment. Cortisol in hair is a promising retrospective stress indicator, as a sample reflects systemic cortisol levels of the past weeks or months. Previous studies have shown that long-term stress with elevated cortisol release can be related to increased cortisol incorporation into the hair shaft. However, potential influencing factors that may affect hair cortisol concentrations (HCCs) must be determined before HCC can be applied as a reliable indicator of stress. The general objectives of this thesis are to investigate influencing factors on HCC, and to examine the potential of hair cortisol concentration as an indicator of long-term stress in cattle and pigs. Thus, the present studies aimed to (1) identify knowledge gaps in hair cortisol research, (2) evaluate the impact of animal-based, seasonal and hair-specific factors as well as contamination and elimination on HCC, and (3) investigate whether and when long-term increased systemic cortisol levels are reflected in elevated HCCs. Hairs were sampled from Holstein Friesian cattle, Landrace or Saddleback pigs and crossbreeds. The findings of the literature review (Study 1) identified potential animal-based, seasonal, hair-specific and stress-related factors on HCCs, which our experimental studies considered. To examine the impact of influencing factors (Study 2), a total of 614 animals were used. Hair samples were taken at different ages (newborn to adult), from different sexes and during both summer and winter. Variations by hair-specific factors were determined by studying black and white hair samples, varying body regions (neck/shoulder, back and tail tip) and different hair segments. In general, female animals were used. The effect of contamination on HCCs was examined in an in vitro study (Study 4) using hair samples from 12 cows and 12 sows. Samples were treated daily with urine, saliva, faeces or water for four weeks or remained untreated. To investigate long-term stress (Study 3), 34 cattle and 38 gilts were injected intramuscularly either with ACTH solution or saline every second day for four weeks. Natural and regrown hair samples were taken before and three times after the end of treatment, and hair segments were collected. All the hair samples were shaved with electric clippers, washed twice with isopropanol and ground with a ball mill. Cortisol was detected by ELISA after extraction with methanol. Statistical analyses were performed using ANOVA and pairwise comparisons of the least square means by Tukey-Kramer tests with the MIXED procedure in SAS/STAT software. The results of Study 2 showed significantly higher HCCs in newborn calves than in young cattle, heifers and cows (p < 0.001). Likewise, 2-week-old piglets had higher HCCs than pigs aged 10 or 27 weeks and sows (p < 0.001). Sex had no effect on HCCs in pigs or cattle. In both species, HCCs were also significantly higher in samples obtained from the tail tip than from the shoulder, neck and back regions (p < 0.001), in black hair than in white hair (p < 0.05) and in distal hair than in proximal hair segments (p < 0.001). Season had an impact on HCC only in cattle, which exhibited higher levels in winter than in summer (p < 0.001). The results of Study 4 showed that contamination with urine caused a considerable concentration-dependent increase in HCCs in both species. Contamination with saliva and faeces also raised HCCs, but only in cattle (all p < 0.05). Treatment with water washed cortisol out from porcine hair but not from bovine hair. In cattle, repeated ACTH application (Study 3) revealed significantly higher HCCs after the end of treatment in natural hair (up to eight weeks, p < 0.001), regrown hair (up to four weeks, p < 0.01) and segmental hair (eight weeks, p < 0.05) than in the control animals. The highest HCCs were found four weeks after the end of treatment. In pigs, elevated HCCs were observed in both ACTH and control animals in all hair sample types after the application period, with no differences between treatments. These results show that hair cortisol concentrations in pigs and cattle are affected by age, body region, hair colour, hair segment and season. There is first evidence that contamination of porcine and bovine hair with cortisol-containing body fluids, such as urine and saliva, may cause the incorporation of external cortisol into the hair shaft. Thus, when using HCC as a potential stress indicator, these influencing factors should be standardised and contamination effects should be avoided, such as by using the shave-reshave procedure, clean sampling regions and only the most proximal hair segments. The results also demonstrated that long-term stress by repeated activation of the HPA axis increases hair cortisol concentrations. In cattle, HCCs in different hair sample types reliably reflected the preceding period with increased systemic cortisol levels. In conclusion, the analysis of HCC appears to be a suitable method to evaluate long-term stress in cattle and pigs and can therefore be an important component in the assessment of animal welfare.:1 General introduction 2 Review of the literature 2.1 The relevance of stress assessment in animal welfare 2.2 Stress response in mammals 2.2.1 Structure and function of the hypothalamic-pituitary-adrenal axis 2.2.2 Characteristics and effects of cortisol 2.2.3 Conventional biological matrices for cortisol analysis 2.3 Hair as a matrix for cortisol analysis 2.3.1 Hair structure and hair types 2.3.2 Hair growth cycle 2.3.3 Incorporation of cortisol into the hair 2.3.3.1 Passive diffusion 2.3.3.2 Multi-compartment model 2.3.4 Elimination of cortisol from the hair 2.3.5 Specific characteristics and applications of hair cortisol 3 Research focuses and aims 4 Results 4.1 Study 1: Hair cortisol for the assessment of stress (review) 4.2 Study 2: Effects of animal-based, seasonal and hair-specific factors on hair cortisol concentrations 4.3 Study 3: Effects of long-term stress on hair cortisol concentrations 4.4 Study 4: Effects of contamination and elimination on hair cortisol concentrations 5 General discussion 5.1 Influencing factors on hair cortisol concentrations in cattle and pigs 5.1.1 Impact of animal-based, seasonal and hair-specific factors 5.1.2 Impact of contamination and elimination by washout 5.1.3 Implications 5.2 Hair cortisol concentration as an indicator of long-term stress in cattle and pigs 5.2.1 Model for the increased release of systemic cortisol 5.2.2 Models for the time course of cortisol incorporation into the hair shaft 5.2.3 Impact of hair sample type and sampling time 5.2.4 Implications Table of contents 5.3 Future perspectives 5.4 Conclusions 6 Summary 7 Zusammenfassung 8 References 9 Danksagung

Measures of temperament including exit velocity (EV) and pen score (PEN) and were compared over 3 repeated observations (60-d interval) of yearling Brahman bulls (initial BW = 320 ± 4 kg; n = 66). Exit velocity measures were correlated; EV1 to EV2 (r = 0.32, P = 0.01), EV1 to EV3 (r = 0.31, P = 0.02), and EV2 to EV3 (r = 0.47, P < 0.001). Both EV and PEN were correlated with serum cortisol (CS) within Time 1 and Time 3; EV1 to CS1 (r = .26, P = 0.04), PEN1 to CS1 (r = 0.29, P = 0.02), and EV3 to CS3 (r = 0.44, P < 0.001). Two-year old Brahman heifer were given an ACTH challenge. The calm (C) and temperamental (T) groups consisted of 6 slow (EV=1.05 ± 0.05 m/sec) and 6 fast (EV = 3.14 ± 0.22 m/sec) heifers. Prior to ACTH challenge, T heifers had elevated CS (T = 48.97 ± 3.42, C = 29.60 ± 5.46 ng/mL). Basal CS was higher (P < 0.001) in T heifers (18.20 ± 2.63, C = 4.30 ± 0.58 ng/mL). Following ACTH (0.1 IU ACTH per kg BW) area under the response curve (AUC) was greater (P = 0.07) in C heifers (T = 69.08 ± 10.69, C = 95.87 ± 7.24 ng·h/mL). After declining below basal concentrations, CS in T heifers were again greater (P = 0.02) than in C heifers. The same heifers were subjected to a CRH challenge (0.1 µg bCRH per kg BW). Prior to CRH area under the ACTH curve was greater (P = 0.025) in T heifers (T = 385.72 ± 49.97, C = 239.24 ± 24.04 pg·h/mL). Basal ACTH did not differ (P = 0.10) between temperament groups. Area under the ACTH response curve was greater (P = 0.057) in C heifers (C = 66.72 ± 10.65, T = 38.11 ± 6.44 pg·h/mL). These data demonstrate that cattle with poor temperament exhibit increased stress responsiveness to handling, increased baseline adrenal function but not increased basal pituitary function, and a muted responsiveness to pharmacological stimulus. Thus functional characteristics of the HPA axis vary with animal temperament.

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Mountain caribou (Rangifer tarandus caribou) are endangered in British Columbia and motorized backcountry recreation has been identified as a potential threat to their persistence. My objective was to test if fecal glucocorticoids (GCs), indicative of physiological effects of ecological stress in wildlife, could be used as a non-invasive tool to quantify stress response in free-ranging caribou exposed to motorized recreation. I validated an enzyme-linked immunosorbent assay (ELISA) to measure concentration of fecal GCs for R. tarandus using an adrenocorticotropic hormone (ACTH) challenge experiment on captive reindeer exposed to extreme variation in winter weather. Female reindeer expressed elevated fecal GCs 9-11 hrs after ACTH injection. Males showed no detectable increase, perhaps due to underdosing. Fecal GCs varied markedly in both sexes in response to natural variation in weather. Overall, my results indicated fecal assays can be used to track biologically meaningful changes in adrenal activity in R.tarandus. I investigated the effects of motorized recreation on stress hormone production by measuring GCs in feces of mountain caribou exposed to snowmobile and heli-ski activity. Concentrations of fecal GCs in snowmobile and heli-ski areas were higher than those measured from caribou in areas where motorized recreation was not allowed. Caribou sampled up to 4km. 8km and I0 km distant from snowmobile activity showed elevated fecal GCs when compared to those sampled further from snowmobile activity areas. Other variables with a significant effect on fecal GCs included reproductive state, snow, aspect. minimum ambient temperature, and daily temperature range. My study indicates that measurement of fecal GCs provides a useful, noninvasive approach in the evaluation of physiological effects of environment, reproductive state, and human-induced stressors on free-ranging mountain caribou. Although research on many species indicates that chronically elevated GCs carry a variety of physiological costs, more study is needed to know whether GCs can be used as an index of human impact on population health or trend.

Bien que l'étiologie de la fibromyalgie (FM) soit inconnue, de l'allodynie, de l'hyperalgésie et un déficit des contrôles inhibiteurs diffus nociceptifs (CIDN) sont rapportés. Une dysfonction de l'axe hypothalamo-hypophyso-surrénalien (HHS) est soupçonnée expliquant la douleur, la fatigue et les troubles du sommeil. La réponse au stress des patients semble inadéquate due à une perte du cycle nycthéméral du cortisol (CORT) et une corrélation CORT/douleur au réveil a déjà été observée. Pourtant, aucune étude n'a investigué le lien entre l'axe HHS et les CIDN. Objectifs: Étudier les CIDN en relation avec les niveaux d'adrénocorticotropine (ACTH) et de CORT, dans la perception et la modulation de la douleur chez des sujets en santé (SS) ou souffrant de FM. Objectifs spécifiques: 1) Étudier et comparer la perception de la douleur des deux groupes (seuils, intensité et aspect désagréable de la douleur, CIDN); 2) Comparer leur cycle circadien du CORT; 3) Comparer la réactivité de l'axe HHS (ACTH plasmatique, CORT salivaire et sérique) des deux groupes en douleur expérimentale; 4) Vérifier la relation entre l'axe HHS, la perception de la douleur et les CIDN. Méthodologie: Devis descriptif corrélationnel entre un groupe de femmes en santé (n=17) et des patientes souffrant de FM (n=19). Leurs cycles circadiens du CORT respectifs ont été comparés par prélèvements salivaires (3 jours consécutifs, 5 fois par jour). Lors de la séance expérimentale, nous avons utilisé le protocole de Tousignant-Laflamme, Y et al. , 2008, pouvant ainsi évaluer les seuils de douleur (SD), seuils de tolérance (ST), intensité (ID) et aspect désagréable (ADD) de la douleur et efficacité des CIDN des deux groupes. Pendant cette même visite, les taux plasmatiques d'ACTH, les niveaux sériques et salivaires du CORT ont été analysés, avant, 5 minutes et 30 minutes après le stimulus douloureux pour étudier la réactivité de l'axe HHS. Des questionnaires ont été administrés pour bien décrire les deux groupes. Résultats: Les résultats sur la perception de la douleur confirment ceux de la littérature : les patientes atteintes de FM ont des SD et des ST plus bas que les SS (allodynie) et leurs CIDN sont inefficaces avec présence d'hyperalgésie, suggérant une anomalie de la composante nociceptive de la douleur. L'ID du stimulus douloureux est identique dans les deux groupes. Pourtant, l'ADD de ce stimulus est supérieur chez les patientes et celles-ci supportent moins longtemps ce stimulus, suggérant l'importance de la composante motivo-affective dans cette pathologie. Les niveaux de base et les cycles circadiens du CORT sont normaux dans les deux groupes. Face à un stimulus douloureux, l'axe HHS des SS est fonctionnel contrairement aux patientes atteintes de FM. Conclusion: il semble que l'axe HHS soit hyporéactif chez les patientes FM, malgré un état basal normal. Il semble y avoir un lien entre l'activité de cet axe, l'efficacité des CIDN et la perception de la douleur.

Classically, testosterone (T) was considered the principal regulator of aggression. However, recent studies in birds have found aggression and T uncoupled during the non-breeding season. Circulating testosterone comes with costs such as immunosuppression and energy expenditure. Instead, the pro-hormone, dehydroepiandrosterone (DHEA), is circulated and activated within the brain via conversion into oestradiol (E2), avoiding the costs associated with T. At present the site of DHEA synthesis is unknown. My thesis investigated the existence of an analogous pathway in non-breeding red squirrels (Tamiasciurus hudsonicus) with two studies: (a) a field study investigating the effects of E2 on aggression and (b) a laboratory study that attempted to determine the site of DHEA synthesis. I conclude that E2 regulates non-breeding aggression in red squirrels and that the adrenals are not the site of DHEA synthesis. My results suggest the existence of a mammalian analogue to the regulatory pathway found in birds.

Classically, testosterone (T) was considered the principal regulator of aggression. However, recent studies in birds have found aggression and T uncoupled during the non-breeding season. Circulating testosterone comes with costs such as immunosuppression and energy expenditure. Instead, the pro-hormone, dehydroepiandrosterone (DHEA), is circulated and activated within the brain via conversion into oestradiol (E2), avoiding the costs associated with T. At present the site of DHEA synthesis is unknown. My thesis investigated the existence of an analogous pathway in non-breeding red squirrels (Tamiasciurus hudsonicus) with two studies: (a) a field study investigating the effects of E2 on aggression and (b) a laboratory study that attempted to determine the site of DHEA synthesis. I conclude that E2 regulates non-breeding aggression in red squirrels and that the adrenals are not the site of DHEA synthesis. My results suggest the existence of a mammalian analogue to the regulatory pathway found in birds.