title: Validation of a Fecal Glucocorticoid Assay to Assess Adrenocortical Activity in Meerkats Using Physiological and Biological Stimuli.
abstract: In mammals, glucocorticoid (i.e. GC) levels have been associated with specific life-history stages and transitions, reproductive strategies, and a plethora of behaviors. Assessment of adrenocortical activity via measurement of glucocorticoid metabolites in feces (FGCM) has greatly facilitated data collection from wild animals, due to its non-invasive nature, and thus has become an established tool in behavioral ecology and conservation biology. The aim of our study was to validate a fecal glucocorticoid assay for assessing adrenocortical activity in meerkats (Suricata suricatta), by comparing the suitability of three GC enzyme immunoassays (corticosterone, 11β-hydroxyetiocholanolone and 11oxo-etiocholanolone) in detecting FGCM increases in adult males and females following a pharmacological challenge with adrenocorticotropic hormone (ACTH) and biological stimuli. In addition, we investigated the time course characterizing FGCM excretion, the effect of age, sex and time of day on FGCM levels and assessed the potential effects of soil contamination (sand) on FGCM patterns. Our results show that the group specific 11β-hydroxyetiocholanolone assay was most sensitive to FGCM alterations, detecting significant and most distinctive elevations in FGCM levels around 25 h after ACTH administration. We found no age and sex differences in basal FGCM or on peak response levels to ACTH, but a marked diurnal pattern, with FGCM levels being substantially higher in the morning than later during the day. Soil contamination did not significantly affect FGCM patterns. Our results emphasize the importance of conducting assay validations to characterize species-specific endocrine excretion patterns, a crucial step to all animal endocrinology studies using a non-invasive approach.
authors.affiliation: Department of Evolutionary Biology and Environmental Studies, Animal Behaviour, University of Zurich, Winterthurerstrasse 190, 8057, Zürich, Switzerland.
authors.forename: Ines
authors.identifier: http://orcid.org/0000-0003-0659-9029
authors.initials: I
authors.lastname: Braga Goncalves
authors.affiliation: Endocrinology Laboratory, German Primate Center, Kellnerweg 4, D-37077, Göttingen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Heistermann
authors.affiliation: Department of Zoology, University of Cambridge, Cambridge, CB2 3EJ, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Santema
authors.affiliation: Department of Zoology, University of Cambridge, Cambridge, CB2 3EJ, United Kingdom.
authors.forename: Ben
authors.initials: B
authors.lastname: Dantzer
authors.affiliation: Department of Evolutionary Biology and Environmental Studies, Animal Behaviour, University of Zurich, Winterthurerstrasse 190, 8057, Zürich, Switzerland.
authors.forename: Jelena
authors.initials: J
authors.lastname: Mausbach
authors.affiliation: Endocrine Research Laboratory, Department of Anatomy and Physiology, University of Pretoria, 0110, Onderstepoort, South Africa.
authors.forename: Andre
authors.initials: A
authors.lastname: Ganswindt
authors.affiliation: Department of Evolutionary Biology and Environmental Studies, Animal Behaviour, University of Zurich, Winterthurerstrasse 190, 8057, Zürich, Switzerland.
authors.forename: Marta B
authors.initials: MB
authors.lastname: Manser
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000738:Androsterone / Q000031:analogs & derivatives / Q000032:analysis; D000818:Animals; D001686:Biological Phenomena; D002851:Chromatography, High Pressure Liquid; D003345:Corticosterone / Q000032:analysis; D005043:Etiocholanolone / Q000032:analysis; D005243:Feces / Q000737:chemistry*; D005260:Female; D005938:Glucocorticoids / Q000032:analysis*; D008988:Herpestidae / Q000502:physiology*; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000502:physiology*; D007118:Immunoassay; D008297:Male; D010829:Physiological Phenomena; D010913:Pituitary-Adrenal System / Q000187:drug effects / Q000502:physiology*; D015203:Reproducibility of Results; D012987:Soil / Q000737:chemistry; D013997:Time Factors
chemical_list: D005938:Glucocorticoids; D012987:Soil; C002528:11 beta-hydroxyandrosterone; D000324:Adrenocorticotropic Hormone; D005043:Etiocholanolone; D000738:Androsterone; D003345:Corticosterone