title: Cortisol Concentrations in Well-Regulated Dogs with Hyperadrenocorticism Treated with Trilostane.
abstract: BACKGROUND
  There are no clear treatment guidelines for dogs with clinically well-regulated hyperadrenocorticism in which serum cortisol concentrations before and after an ACTH stimulation test performed 3-6 hours after trilostane administration are < 2.0 μg/dL.
  
  
  OBJECTIVE
  To determine if serum cortisol concentrations measured before (Pre1) and after (Post1) ACTH stimulation at 3-6 hours after trilostane administration are significantly lower than cortisol concentrations measured before (Pre2) and after (Post2) ACTH stimulation 9-12 hours after trilostane administration, in a specific population of dogs with clinically well-regulated hyperadrenocorticism and Pre1 and Post1 <2 μg/dL.
  
  
  METHODS
  Thirteen client-owned dogs with clinically well-regulated hyperadrenocorticism and Pre1 and Post1 serum cortisol concentrations <2.0 μg/dL 3-6 hours after trilostane administration.
  
  
  METHODS
  Prospective study. Dogs had a second ACTH stimulation test performed 9-12 hours after trilostane administration, on the same day of the first ACTH stimulation test. Cortisol concentrations before and after ACTH stimulation were compared using a paired t-test.
  
  
  RESULTS
  Cortisol concentrations before (1.4 ± 0.3 μg/dL) and after the first stimulation (1.5 ± 0.3 μg/dL, mean ± SD) were significantly lower than cortisol concentration before the second stimulation (3.3 ± 1.6 μg/dL, P = .0012 each). Cortisol concentration before the first stimulation was also significantly lower than cortisol concentration after the second stimulation (5.3 ± 2.4 μg/dL, P = .0001).
  
  
  CONCLUSIONS
  In dogs with clinically well-regulated, trilostane-treated, hyperadrenocorticism, and cortisol concentrations <2 μg/dL before and after the first stimulation, a second ACTH stimulation test performed 9-12 hours after treatment can result in higher cortisol concentrations that could support continued trilostane treatment.
authors.affiliation: Department of Clinical Studies - Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA.
authors.forename: J N
authors.initials: JN
authors.lastname: Midence
authors.affiliation: Department of Clinical Studies - Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Drobatz
authors.affiliation: Department of Clinical Studies - Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA.
authors.forename: R S
authors.initials: RS
authors.lastname: Hess
mesh_terms: D000309:Adrenal Insufficiency / Q000188:drug therapy / Q000662:veterinary*; D000818:Animals; D013196:Dihydrotestosterone / Q000031:analogs & derivatives* / Q000627:therapeutic use; D004283:Dog Diseases / Q000097:blood / Q000188:drug therapy*; D004285:Dogs; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D006854:Hydrocortisone / Q000097:blood*
chemical_list: D004791:Enzyme Inhibitors; D013196:Dihydrotestosterone; C009954:trilostane; D006854:Hydrocortisone
keywords: Adrenocorticotropic hormone stimulation test; Cushing's disease; Hyperkalemia; Hypoadrenocorticism; lymphocytosis