Kemppainen R J, Zenoble R D
J Am Vet Med Assoc. 1985 Aug 1;187(3):276-8.
A 5-year-old female dog with hyperadrenocorticism was determined to have pituitary-dependent hyperadrenocorticism even though plasma cortisol concentrations were not suppressed after high-dosage dexamethasone administration. The diagnosis was based on a supranormal response of plasma cortisol to ACTH administration and a lack of suppression of plasma cortisol concentration after administration of 0.1 mg of dexamethasone/kg. Although a higher dosage of dexamethasone (1 mg/kg) did not cause suppression of plasma cortisol, plasma ACTH concentrations in the dog were increased above those in clinically normal dogs, supporting a diagnosis of pituitary-dependent hyperadrenocorticism. During treatment with mitotane, the dog became unconscious and died. Necropsy revealed a pituitary tumor that had compressed and displaced the hypothalamus. Although high-dosage dexamethasone suppression tests often are useful in the differential diagnosis of hyperadrenocorticism, a lack of suppression of plasma cortisol does not necessarily exclude pituitary-dependent hyperadrenocorticism.
一只患有肾上腺皮质功能亢进的5岁雌性犬，尽管高剂量地塞米松给药后血浆皮质醇浓度未被抑制，但仍被确定为垂体依赖性肾上腺皮质功能亢进。诊断依据是血浆皮质醇对促肾上腺皮质激素（ACTH）给药的超常反应，以及给予0.1mg地塞米松/千克后血浆皮质醇浓度未被抑制。尽管更高剂量的地塞米松（1mg/千克）未导致血浆皮质醇被抑制，但该犬的血浆促肾上腺皮质激素浓度高于临床正常犬，支持垂体依赖性肾上腺皮质功能亢进的诊断。在用米托坦治疗期间，该犬昏迷并死亡。尸检发现一个垂体肿瘤，该肿瘤压迫并移位了下丘脑。尽管高剂量地塞米松抑制试验通常有助于肾上腺皮质功能亢进的鉴别诊断，但血浆皮质醇未被抑制并不一定排除垂体依赖性肾上腺皮质功能亢进。
