title: Twenty-four-hour profiles of metabolic and stress hormones in sheep selected for a calm or nervous temperament.
abstract: Even in the absence of stressors, temperament is associated with changes in the concentration of stress-responsive hormones and, possibly because of such changes, temperament can affect metabolism. We tested whether, in sheep bred for temperament for 14 generations, "nervous" females have greater concentrations of stress-responsive hormones in the absence of stressors than "calm" females, and whether these differences are associated with changes in the concentrations of metabolic hormones. In resting "calm" (n = 8) and "nervous" (n = 8) sheep, concentrations of cortisol, prolactin, leptin, and insulin were measured in blood plasma sampled via jugular catheter every 20 min for 24 h. The animals were individually penned, habituated to their housing and human handling over 7 wk, and fed before sampling began. Diurnal variation was evident for all hormones, but a 24-h cortisol pattern was detected in only 7 individuals. There was no effect of temperament on any aspect of concentrations of cortisol or prolactin, but "calm" animals had greater concentrations of insulin in the early afternoon than "nervous" animals (14.5 ± 1.1 vs 10.0 ± 1.6 μU/mL; P = 0.038), and a similar tendency was seen for leptin (P = 0.092). We conclude that selection for temperament affects the concentration of metabolic hormones in the absence of stressors, but this effect is independent of stress-responsive hormones.
authors.affiliation: The UWA Institute of Agriculture, The University of Western Australia, Crawley, Western Australia, 6009, Australia; The School of Animal Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia.
authors.forename: S E
authors.initials: SE
authors.lastname: Rietema
authors.affiliation: The UWA Institute of Agriculture, The University of Western Australia, Crawley, Western Australia, 6009, Australia; The School of Animal Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia.
authors.forename: M A
authors.initials: MA
authors.lastname: Blackberry
authors.affiliation: The School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia.
authors.forename: S K
authors.initials: SK
authors.lastname: Maloney
authors.affiliation: The UWA Institute of Agriculture, The University of Western Australia, Crawley, Western Australia, 6009, Australia; The School of Animal Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia.
authors.forename: G B
authors.initials: GB
authors.lastname: Martin
authors.affiliation: The UWA Institute of Agriculture, The University of Western Australia, Crawley, Western Australia, 6009, Australia; The School of Animal Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia.
authors.forename: P A R
authors.initials: PA
authors.lastname: Hawken
authors.affiliation: The UWA Institute of Agriculture, The University of Western Australia, Crawley, Western Australia, 6009, Australia; The School of Animal Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia. Electronic address: dominique.blache@uwa.edu.au.
authors.forename: D
authors.initials: D
authors.lastname: Blache
mesh_terms: D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006854:Hydrocortisone / Q000097:blood; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000097:blood; D010913:Pituitary-Adrenal System / Q000502:physiology; D011388:Prolactin / Q000097:blood; D012641:Selection, Genetic; D012756:Sheep / Q000235:genetics* / Q000502:physiology*; D013312:Stress, Physiological / Q000502:physiology*; D013694:Temperament / Q000502:physiology*
chemical_list: D007328:Insulin; D020738:Leptin; D011388:Prolactin; D006854:Hydrocortisone
keywords: Cortisol; Hypothalamo-pituitary-adrenal axis; Insulin; Leptin; Prolactin; Temperament