title: Comparison of mitotane treatment for adrenal tumor versus pituitary-dependent hyperadrenocorticism in dogs.
abstract: The purpose of this study was to determine the sensitivity of dogs with hyperadrenocorticism to treatment with the adrenocorticolytic agent mitotane. Specifically, we looked for differences in response to treatment using this drug in dogs with adrenocortical tumors (adrenal tumor hyperadrenocorticism, ATH) vs those with pituitary-dependent hyperadrenocorticism (PDH). For inclusion in this study, each dog must have had clinical signs, data base laboratory abnormalities, and endocrine screening test results consistent with the diagnosis of hyperadrenocorticism. Further, each dog had to have been treated for at least 6 months with mitotane and have histologic evidence for adrenocortical or pituitary neoplasia (all dogs were necropsied). Thirteen dogs with ATH (8 carcinomas, 5 adenomas) were identified. The ages and body weights of these 13 dogs were computer-matched to 13 dogs with PDH. All dogs were initially treated with approximately 50 mg of mitotane/kg/d of body weight. Reexaminations were performed after 7, 30, 90, and 180 days of treatment. Individual dosages varied widely after the initial 5 to 12 days of treatment. The mean (+/- SD) dose of mitotane (mg/kg/d) for the first 7 days of treatment was 47.5 +/- 9.4 for dogs with ATH vs 45.7 +/- 11.9 for dogs with PDH. The mean plasma cortisol concentrations 1 hour after ACTH administration at the 7-day recheck were significantly higher in dogs with ATH (502 +/- 386 nmol/L) than in dogs with PDH (88 +/- 94 nmol/L).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Reproduction, School of Veterinary Medicine, University of California, Davis 95616.
authors.forename: E C
authors.initials: EC
authors.lastname: Feldman
authors.forename: R W
authors.initials: RW
authors.lastname: Nelson
authors.forename: M S
authors.initials: MS
authors.lastname: Feldman
authors.forename: T B
authors.initials: TB
authors.lastname: Farver
mesh_terms: D000236:Adenoma / Q000150:complications / Q000188:drug therapy / Q000662:veterinary; D000302:Adrenal Cortex / Q000473:pathology; D000310:Adrenal Gland Neoplasms / Q000150:complications / Q000188:drug therapy / Q000662:veterinary*; D000308:Adrenocortical Hyperfunction / Q000188:drug therapy / Q000209:etiology / Q000662:veterinary*; D000324:Adrenocorticotropic Hormone; D000818:Animals; D002277:Carcinoma / Q000150:complications / Q000188:drug therapy / Q000662:veterinary; D004283:Dog Diseases / Q000188:drug therapy* / Q000209:etiology; D004285:Dogs; D006854:Hydrocortisone / Q000097:blood; D008939:Mitotane / Q000627:therapeutic use*
chemical_list: D008939:Mitotane; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone