Evaluation of the basal and post-adrenocorticotrophic hormone serum concentrations of 17-hydroxyprogesterone for the diagnosis of hyperadrenocorticism in dogs

Serum concentrations of 17-hydroxyprogesterone and cortisol were measured before and after the administration of exogenous adrenocorticotrophic hormone (ACTH) to three groups of dogs: 27 healthy dogs (group 1), 19 dogs with non-adrenal illness (group 2) and 46 dogs with hyperadrenocorticism (group 3). The median (range) post-ACTH concentrations of 17-hydroxyprogesterone were 5.0 (22.2 to 16.8), 6.9 (2.0 to 36.2) and 14.4 (1.7 to 71) nmol/litre in groups 1, 2 and 3, respectively. There were no significant differences in the basal or post-ACTH concentrations of cortisol or 17-hydroxyprogesterone between groups 1 and 2. The post-ACTH concentrations of 17-hydroxyprogesterone in group 3 were significantly (P