Effect of Trilostane and Mitotane on Aldosterone Secretory Reserve in Dogs with Pituitary‐Dependent Hyperadrenocorticism

• Published in: Journal of veterinary internal medicine Vol. 28; no. 2; pp. 443 - 450
• Main Authors: Reid, L.E, Behrend, E.N, Martin, L.G, Kemppainen, R.J, Ward, C.R, Lurye, J.C, Donovan, T.C, Lee, H.P
• Format: Journal Article
• Language: English
• Published: United States J.B. Lippincott 01.03.2014; Blackwell Publishing Ltd; John Wiley & Sons, Inc; John Wiley and Sons Inc
• Subjects: aldosterone; Aldosterone - blood; Aldosterone - secretion; Animals; blood serum; corticotropin; cortisol; Cushing's disease; Dihydrotestosterone - analogs & derivatives; Dihydrotestosterone - therapeutic use; Dog Diseases - blood; Dog Diseases - drug therapy; Dog Diseases - physiopathology; Dogs; electrolytes; Female; Hormones; Hydrocortisone - blood; hyperadrenocorticism; Lysodren; Male; medicine; mitotane; Mitotane - therapeutic use; Original; Pituitary ACTH Hypersecretion - blood; Pituitary ACTH Hypersecretion - drug therapy; Pituitary ACTH Hypersecretion - physiopathology; Pituitary ACTH Hypersecretion - veterinary; Pituitary-dependent hyperadrenocorticism; potassium; Potassium - blood; secretion; sodium; Sodium - blood; Vetoryl; Vetoryl; Lysodren; Pituitary-dependent hyperadrenocorticism; Cushing's disease
• ISSN: 0891-6640; 1939-1676
• DOI: 10.1111/jvim.12276

BACKGROUND: Maximal aldosterone secretion in healthy dogs occurs 30 minutes postadrenocorticotropin (ACTH; 5 μg/kg IV) stimulation. The effect of trilostane and mitotane on aldosterone at that time is unknown. OBJECTIVES: To assess the effect of trilostane and mitotane in dogs with pituitary‐dependent hyperadrenocorticism on aldosterone secretory reserve. To determine if aldosterone concentration correlates with electrolyte concentrations. ANIMALS: Serum collected from 79 client‐owned dogs and 33 stored samples. METHODS: Client‐owned dogs had ACTH stimulation tests with cortisol concentrations measured at 0 and 60 minutes and aldosterone concentrations measured at 0, 30, and 60 minutes. Stored samples had aldosterone concentrations measured at 0 and 60 minutes. Ten historical clinically healthy controls were included. All had basal sodium and potassium concentrations measured. RESULTS: The aldosterone concentrations in the mitotane‐ and trilostane‐treated dogs at 30 and 60 minutes post‐ACTH were significantly lower than in clinically healthy dogs; no significant difference was detected in aldosterone concentration between 30 and 60 minutes in treated dogs. However, a significantly higher percentage of dogs had decreased aldosterone secretory reserve detected at 30 minutes than at 60 minutes. At 30 minutes, decreased secretory reserve was detected in 49% and 78% of trilostane‐ and mitotane‐treated dogs, respectively. No correlation was detected between aldosterone and serum electrolyte concentrations. CONCLUSIONS AND CLINICAL IMPORTANCE: Decreased aldosterone secretory reserve is common in trilostane‐ and mitotane‐treated dogs; it cannot be predicted by measurement of serum electrolyte concentrations. Aldosterone concentration at 30 minutes post‐ACTH stimulation identifies more dogs with decreased aldosterone secretory reserve than conventional testing at 60 minutes.