title: Serum cortisol concentrations in dogs with pituitary-dependent hyperadrenocorticism and atypical hyperadrenocorticism.
abstract: BACKGROUND
  Atypical hyperadrenocorticism (AHAC) is considered when dogs have clinical signs of hypercortisolemia with normal hyperadrenocorticism screening tests.
  
  
  OBJECTIVE
  To compare cortisol concentrations and adrenal gland size among dogs with pituitary-dependent hyperadrenocorticism (PDH), atypical hyperadrenocorticism (AHAC), and healthy controls.
  
  
  METHODS
  Ten healthy dogs, 7 dogs with PDH, and 8 dogs with AHAC.
  
  
  METHODS
  Dogs were prospectively enrolled between November 2011 and January 2013. Dogs were diagnosed with PDH or AHAC based on clinical signs and positive screening test results (PDH) or abnormal extended adrenal hormone panel results (AHAC). Transverse adrenal gland measurements were obtained by abdominal ultrasound. Hourly mean cortisol (9 samplings), sum of hourly cortisol measurements and adrenal gland sizes were compared among the 3 groups.
  
  
  RESULTS
  Hourly (control, 1.4 ± 0.6 μg/dL; AHAC, 2.9 ± 1.3; PDH, 4.3 ± 1.5) (mean, SD) and sum (control, 11.3 ± 3.3; AHAC, 23.2 ± 7.7; PDH, 34.7 ± 9.9) cortisol concentrations differed significantly between the controls and AHAC (P < .01) and PDH (P < .01) groups. Hourly (P < .01) but not sum (P = .27) cortisol concentrations differed between AHAC and PDH dogs. Average transverse adrenal gland diameter of control dogs (5.3 ± 1.2 mm) was significantly less than dogs with PDH (6.4 ± 1.4; P = .02) and AHAC (7.2 ± 1.5; P < .01); adrenal gland diameter did not differ (P = .18) between dogs with AHAC and PDH.
  
  
  CONCLUSIONS
  Serum cortisol concentrations in dogs with AHAC were increased compared to controls but less than dogs with PDH, while adrenal gland diameter was similar between dogs with AHAC and PDH. These findings suggest cortisol excess could contribute to the pathophysiology of AHAC.
authors.affiliation: Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN.
authors.forename: L A
authors.initials: LA
authors.lastname: Frank
authors.forename: G A
authors.initials: GA
authors.lastname: Henry
authors.forename: J C
authors.initials: JC
authors.lastname: Whittemore
authors.forename: B D
authors.initials: BD
authors.lastname: Enders
authors.forename: D I
authors.initials: DI
authors.lastname: Mawby
authors.forename: B W
authors.initials: BW
authors.lastname: Rohrbach
mesh_terms: D000311:Adrenal Glands / Q000473:pathology; D000308:Adrenocortical Hyperfunction / Q000145:classification / Q000473:pathology / Q000662:veterinary*; D000818:Animals; D004283:Dog Diseases / Q000097:blood* / Q000473:pathology; D004285:Dogs; D005260:Female; D006854:Hydrocortisone / Q000097:blood*; D008297:Male
chemical_list: D006854:Hydrocortisone
keywords: Adrenal; Atypical Cushing's Syndrome; Endocrine