The ACTH stimulation test, dexamethasone suppression test and metyrapone stimulation test are useful biochemical tests employed to differentiate disease processes involving increased cortisol production by adrenocortical hyperplasia, adrenocortical adenoma, adrenocortical carcinoma and the ectopic ACTH syndrome. Metyrapone, a pharmacological inhibitor of adrenocortical 11β-hydroxylase activity, partially inhibits cortisol production and thus stimulates ACTH release, resulting in increased urine levels of 17-OHCS. Patients with adrenocortical adenomas are not expected to respond to metyrapone. The present case, with Cushing’s syndrome due to an adrenocortical adenoma, presents an exception to the expected test responses in that there was an increase in urinary 17-OHCS due to administration of metyrapone.
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Clinical Biochemistry
- Biochemistry, medical