Cortisol and aldosterone response to various doses of cosyntropin in healthy cats.
Author(s): DeClue AE, Martin LG, Behrend EN, Cohn LA, Dismukes DI, Lee HP
Affiliation(s): Comparative Internal Medicine Laboratory, Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA. decluea@Missouri.edu
Publication date & source: 2011-01-15, J Am Vet Med Assoc., 238(2):176-82.
Publication type: Research Support, Non-U.S. Gov't
OBJECTIVE: To determine the lowest dose of cosyntropin on a per body weight basis that would produce maximal cortisol and aldosterone secretion and the ideal timing of blood sample collection after ACTH stimulation in healthy cats. DESIGN: Randomized crossover trial. ANIMALS: 7 adult sexually intact male purpose-bred cats. PROCEDURES: Each cat received saline (0.9% NaCl) solution (control) and 5 doses (125 mug/cat and 10, 5, 2.5, and 1 mug/kg [4.54, 2.27, 1.14, and 0.45 mug/lb]) of cosyntropin IV with a 2-week washout period between treatments. Blood samples were obtained before (baseline) and at 15, 30, 45, 60, 75, and 90 minutes after administration of saline solution or cosyntropin. RESULTS: Serum cortisol and aldosterone concentration increased significantly, compared with baseline values, after administration of all cosyntropin doses. Lower doses of cosyntropin resulted in an adrenocortical response equivalent to the traditional dose of 125 mug/cat. The lowest doses of cosyntropin that stimulated a maximal cortisol and aldosterone response were 5 and 2.5 mug/kg, respectively. Lower doses of cosyntropin resulted in a shorter interval between IV administration of cosyntropin and peak serum cortisol and aldosterone concentrations. CONCLUSIONS AND CLINICAL RELEVANCE: Low-dose ACTH stimulation testing with IV administration of cosyntropin at 5 mug/kg followed by blood sample collection at 60 to 75 minutes resulted in concurrent peak serum cortisol and aldosterone concentrations that were equivalent to those achieved following administration of cosyntropin at 125 mug/cat, the standard dose currently used.