• Open Access

Plasma ACTH Precursors in Cats with Pituitary-Dependent Hyperadrenocorticism


  • Part of this work was presented at the 2008 ACVIM Forum, Seattle, WA; at the annual ECVIM-CA Congress, in Ghent, Belgium, September 2008 (winner of the ESVE abstract award); and at the 2009 ACVIM Forum and Canadian Veterinary Medical Association Convention, Montreal, Quebec, Canada.

Corresponding author: Dan Rosenberg, DVM, PhD. Internal Medicine Unit, Université Paris-Est, Ecole Nationale Vétérinaire d'Alfort, 7 avenue du Général de Gaulle, 94704, Maisons-Alfort, France; e-mail: rosenberg@vet-alfort.fr



Diagnosis of pituitary-dependent hyperadrenocorticism (PDH) in cats is challenging because there is no specific diagnostic test.


The determination of plasma ACTH precursor (POMC and pro-ACTH) concentration might facilitate the diagnosis of PDH in cats. The aim of the study was to evaluate prospectively the plasma concentrations of ACTH precursors in a small cohort of cats with PDH and to estimate the value of this approach for diagnosis.


Four groups of cats were included: group 1 (cats with PDH), group 2 (cats with diabetes mellitus but not hyperadrenocorticism (HAC)), group 3 (cats with diabetes mellitus and confirmed acromegaly but not HAC), and group 4 (healthy cats).


PDH diagnosis was based on clinical data, low-dose dexamethasone suppression test (LDDST), and adrenal and pituitary gland computed tomography (CT) scan. For groups 2, 3, and 4, hyperadrenocorticism was excluded by LDDST or urine cortisol:creatinine ratio (UCCR). An immunoluminometric assay was used to determine plasma concentrations of ACTH precursors in the 4 groups of cats.


Group 1 contained 9 cats (enlarged pituitary gland in 7/9). Plasma ACTH precursor concentrations ranged from <53 to >1010 pmol/L with 8/9 concentrations ≥229 pmol/L. Groups 2, 3, and 4 included 13, 7, and 13 cats, respectively. Plasma ACTH precursor concentrations ranged from <53 to 96 pmol/L in group 2, <53 to 72 pmol/L in group 3, and <53 to 99 pmol/L in group 4.

Conclusion and Clinical Importance

High plasma concentration of ACTH precursors in cats (>100 pmol/L) is highly suggestive of PDH.