title: Baseline plasma cortisol and ACTH concentrations and response to low-dose ACTH stimulation testing in ill foals.
abstract: OBJECTIVE
  To evaluate baseline plasma cortisol and ACTH concentrations and responses to low-dose ACTH stimulation testing in ill foals.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  58 ill foals.
  
  
  METHODS
  Baseline cortisol and ACTH concentrations and cortisol concentrations after administration of a low dose of cosyntropin were determined within 6 hours after admission. Foals were assigned to 4 groups on the basis of age (<or=24 hours vs 1 to 56 days) and presence of septicemia (yes vs no). Values were compared among groups and with values previously reported for healthy foals.
  
  
  RESULTS
  Plasma cortisol concentrations 30 and 60 minutes after cosyntropin administration in foals<or=24 hours old were significantly higher than corresponding cortisol concentrations in older foals. In all 4 groups, plasma cortisol concentration 30 minutes after cosyntropin administration was significantly higher than baseline cortisol concentration or concentration 60 minutes after cosyntropin administration. No differences in baseline cortisol or ACTH concentration or in the ACTH-to-cortisol ratio were detected between groups or when ill foals were compared with healthy foals. A small number of ill foals had low baseline cortisol and ACTH concentrations or low responses to cosyntropin administration, compared with healthy foals.
  
  
  CONCLUSIONS
  Results indicated that most ill foals in the present study population had adequate responses to cosyntropin administration. However, a small subset of ill foals appeared to have dysfunction of the hypothalamic-pituitary-adrenal axis.
authors.affiliation: Department of Veterinary Clinical Sciences, Iowa State University, Ames, IA 50011, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Wong
authors.forename: Dai Tan
authors.initials: DT
authors.lastname: Vo
authors.forename: Cody J
authors.initials: CJ
authors.lastname: Alcott
authors.forename: Anna D
authors.initials: AD
authors.lastname: Peterson
authors.forename: Brett A
authors.initials: BA
authors.lastname: Sponseller
authors.forename: Walter H
authors.initials: WH
authors.lastname: Hsu
mesh_terms: D000302:Adrenal Cortex / Q000502:physiology; D000304:Adrenal Cortex Function Tests / Q000379:methods / Q000662:veterinary*; D000309:Adrenal Insufficiency / Q000175:diagnosis / Q000662:veterinary*; D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D019540:Area Under Curve; D003366:Cosyntropin / Q000493:pharmacokinetics*; D003430:Cross-Sectional Studies; D005260:Female; D006734:Horse Diseases / Q000175:diagnosis*; D006736:Horses; D006854:Hydrocortisone / Q000097:blood*; D008297:Male
chemical_list: D003366:Cosyntropin; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone