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Evaluation of serum 17-hydroxyprogesterone concentration after administration of ACTH in dogs with hyperadrenocorticism

Noémi Benitah DVM, DACVIM1,2, Edward C. Feldman DVM, DACVIM3, Philip H. Kass DVM, PhD, DACVPM4, and Richard W. Nelson DVM, DACVIM5
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  • 1 Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, CA 95616.
  • | 2 Present address is Red Bank Veterinary Hospital, 197 Hance Ave, Tinton Falls, NJ 07724.
  • | 3 Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616.
  • | 4 Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA 95616.
  • | 5 Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616.

Abstract

Objective—To evaluate serum 17-hydroxyprogesterone (17-OHP) concentration measurement after administration of ACTH for use in the diagnosis of hyperadrenocorticism in dogs.

Design—Prospective study.

Animals—110 dogs.

Procedure—Serum 17-OHP concentrations were measured before and after ACTH stimulation in 53 healthy dogs to establish reference values for this study. Affected dogs had pituitary-dependent (n = 40) or adrenal tumor–associated (12) hyperadrenocorticism or potentially had atypical hyperadrenocorticism (5; diagnosis confirmed in 1 dog). In affected dogs, frequency interval and borderline and abnormal serum 17-OHP concentrations after ACTH stimulation were determined. Serum cortisol concentrations were assessed via low-dose dexamethasone suppression and ACTH stimulation tests.

Results—In healthy dogs, serum 17-OHP concentration frequency intervals were grouped by sex and reproductive status (defined as < 95th percentile). Frequency intervals of serum 17-OHP concentrations after ACTH stimulation were < 7.7, < 2.0, < 3.2, and < 3.4 ng/mL (< 23.3, < 6.1, < 9.7, and < 10.3 nmol/L) for sexually intact and neutered females and sexually intact and neutered males, respectively. In 53 dogs with confirmed hyperadrenocorticism, serum cortisol concentrations after ACTH stimulation and 8 hours after administration of dexamethasone and serum 17- OHP concentrations after ACTH stimulation were considered borderline or abnormal in 79%, 93%, and 69% of dogs, respectively. Two of 5 dogs considered to have atypical hyperadrenocorticism had abnormal serum 17-OHP concentrations after ACTH stimulation.

Conclusions and Clinical Relevance—Serum 17-OHP concentration measurement after ACTH stimulation may be useful in the diagnosis of hyperadrenocorticism in dogs when other test results are equivocal. (J Am Vet Med Assoc 2005;227:1095–1101)