title: Progesterone pretreatment increases the stress response to social isolation in ewes.
abstract: OBJECTIVE
  In rodents, progesterone (P4) pretreatment increases anxiety and response to stressors. Social isolation is a stressor that generates physiological and behavioural stress responses in sheep. The aim of the study was to compare the stress response of anoestrous ewes previously treated or not with P4 to the social isolation test.
  
  
  METHODS
  Ten ewes received P4 treatment during 13 d (group P4-W) and another 10 remained untreated as controls (group Con). The ewes were individually isolated in a novel place during 10 min, 24 h after the end of P4 pretreatment and their behaviours were recorded. Cortisol and P4 concentrations as well as body surface temperature were recorded before and after the test.
  
  
  RESULTS
  Ewes of the P4-W group presented higher cortisol levels 0, 10, 20 and 30 min after the social isolation and had greater area under the curve of cortisol compared to Con ewes (41,785%±4,156% vs. 25,682%±4,565% during 75 min). Progesterone and body surface temperature increased after social isolation, with no differences between P4-W and Con ewes. There were no differences in behavioural responses to social isolation.
  
  
  CONCLUSIONS
  P4 pretreatment appears to augment the stress response to social isolation in anoestrous ewes.
authors.affiliation: Departamento de Biología Molecular y Celular, Facultad de Veterinaria, Universidad de la República, Lasplaces, Montevideo, Uruguay.
authors.forename: Aline
authors.initials: A
authors.lastname: Freitas-de-Melo
authors.affiliation: Departamento de Biología Molecular y Celular, Facultad de Veterinaria, Universidad de la República, Lasplaces, Montevideo, Uruguay.
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Damián
authors.affiliation: Laboratório de Etologia Aplicada, Departamento de Zootecnia e Desenvolvimento Rural, Universidade Federal de Santa Catarina, Rodovia Admar Gonzaga, Florianópolis, Brazil.
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Hötzel
authors.affiliation: Instituto Nacional de Investigación Agropecuaria, La Estanzuela, Colonia, Uruguay.
authors.forename: Georgget
authors.initials: G
authors.lastname: Banchero
authors.affiliation: Departamento de Fisiología, Facultad de Veterinaria, Universidad de la República, Lasplaces, Montevideo, Uruguay.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Ungerfeld
mesh_terms: D000818:Animals; D001831:Body Temperature; D004334:Drug Administration Schedule; D005260:Female; D006854:Hydrocortisone / Q000097:blood; D011374:Progesterone / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D011372:Progestins / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D012756:Sheep / Q000097:blood* / Q000502:physiology; D012934:Social Isolation; D013312:Stress, Physiological / Q000187:drug effects* / Q000502:physiology
chemical_list: D011372:Progestins; D011374:Progesterone; D006854:Hydrocortisone