Research Communications of the 27(th) ECVIM-CA Congress: Intercontinental, Saint Julian's, Malta, 14th to 16th September 2017

Disclosures: No disclosures to report. is a common endocrine disorder in dogs. At present, medical management of canine PDH consists of either trilostane or mitotane therapy. Both treatments have disadvantages associated with the induction of hypoadrenocorticism. Therefore, a more specific inhibition of glucocorticoid synthesis is desirable. Our recent studies indicate that the steroidogenic enzyme cytochrome P-450c17 (CYP17) could be an interesting target for selective inhibition of cortisol production without impeding the synthesis of aldosterone. Abiraterone acetate (AA), a highly selective irreversible CYP17inhibitor, is already available on the market and successfully used for the treatment of castration-resistant prostate cancer in humans. In addition, the registration for human application will probably enable a relatively straightforward implementation into veterinary clinical practice. As side effects of AA are mostly related to hypocortisolism, this approach seems interesting as a novel medical treatment option for canine hypercortisolism. The aim of this study was to determine the effects of AA on cortisol synthesis; on mRNA expression of steroidogenic genes encoding for CYP17, 3b-hydroxysteroid dehydrogenase (3b-HSD) and Ki67, a cellular marker for proliferation; and on adrenocortical cell viability.