EFFECTS OF DELMADINONE ACETATE ON PITUITARY-ADRENAL-FUNCTION, GLUCOSE-TOLERANCE AND GROWTH-HORMONE IN MALE DOGS

Objective To characterise the effects of delmadinone acetate on the pi tuitary-adrenal axis, glucose tolerance and growth hormone concentrati on in normal male dogs and dogs with benign prostatic hyperplasia. Des ign A prospective study involving nine normal male dogs and seven with prostatic hyperplasia. Procedure Delmadinone acetate was administered to six normal male dogs and seven dogs with benign prostatic hyperpla sia at recommended dose rates (1.5 mg/kg subcutaneously at 0, 1 and 4 weeks). Three normal controls received saline at the same intervals. B lood concentrations of ACTH, cortisol, glucose, insulin and growth hor mone were measured over 50 days. Intravenous glucose tolerance and ACT H response tests were performed before and after treatment in the nine normal animals. Results A substantial suppression of basal and 2 h po st ACTH plasma cortisol secretion was demonstrated after one dose in a ll dogs given delmadinone acetate. Individual responses after the seco nd and third administration varied between recovery in adrenal respons iveness to continued suppression. Plasma ACTH concentration was also d iminished after one treatment. No effects were evident on glucose tole rance or serum growth hormone concentrations. Conclusion Delmadinone a cetate causes adrenal suppression from inhibition of release of ACTH f rom the pituitary gland. Treated dogs may be at risk of developing sig ns of glucocorticoid insufficiency if subjected to stressful events du ring or after therapy. Neither glucose intolerance nor hyper-somatotro pism seems likely in male dogs given delmadinone acetate at the recomm ended dose rate, but the potential for excessive growth hormone secret ion in treated bitches remains undetermined.