Research Communications of the 24th ECVIM-CA Congress

No conflicts of interest reported. The cortisol-dehydroepiandrosterone (DHEA)-ratio is widely used in human medicine as a marker for stress however it is not clear whether it could also help in distinguishing hyperadrenocorticism (HAC) from other diseases which might have a negative impact on the outcome of a dexamethasone low dose test. Therefore the aim of the study was to evaluate the cortisol-DHEA-ratio as an additional diagnostic marker for HAC in dogs. To achieve this aim, a reference range of this ratio depending on the sex should be evaluated in healthy dogs and compared with dogs having a HAC. In 55 healthy dogs (age: 1 -11.4 years) and in 20 dogs with HAC (age: 7.1 -14.6 years) of different breeds the plasma concentration of cortisol (Immulite System, Siemens Healthcare Diagnostics) and DHEA (Beckman Coulter) was measured and the ratio was calculated. All dogs were patients of the Small Animal Clinic except five of the healthy dogs which were recruited from the Institute of Pharmacology, Toxicology and Pharmacy of the University. With these data the cortisol-DHEA-ratio was calculated for male dogs (healthy dogs n = 18; dogs with HAC n = 3), neutered males (healthy dogs n = 9; dogs with HAC n = 5), female dogs (healthy dogs n = 21; dogs with HAC n = 5) and spayed females (healthy dogs n = 7; dogs with HAC n = 7). The statistical analysis was performed with Sigma Stat. The plasma cortisol-DHEA-ratio of healthy male dogs was the lowest ratio of all sexual categories (mean average 84.8 AE 128) and it differed significantly to all other sexes (neutered males = 231 AE 138, P = 0.002; females = 244 AE 124, P < 0.001 and spayed females (183 AE 60.0, P = 0.006). The cortisol-DHEA-ratio showed no significant difference between male and female dogs with HAC. Spayed females with HAC had significantly higher cortisol-DHEA-ratios (501 AE 310) than healthy spayed females (P = 0.035) but no significant differences were found in other sexual categories. This preliminary data indicates that the cortisol-DHEA-ratio might not be a very promising tool for the diagnosis of HAC. In addition, the significant gender-dependency of this parameter has to be considered and may generally limit its clinical usefulness. This study is financially supported by the Bruns-Stiftung.