Deoxycorticosterone and aldosterone excretion in Cushing's syndrome

We have used specific radioimmunoassays to measure urinary free deoxycorticosterone (DOC) and total aldosterone excretion in 15 patients with Cushing's syndrome. Free DOC excretion was increased in 6 of 8 patients with pituitary-dependent adrenal hyperplasia, in 2 of 3 patients with adrenal adenoma, and in all 4 cases with adrenal carcinoma. The most marked increase was noted in the adrenal carcinoma cases. Aldosterone excretion was high, normal, or low in each of the three types of Cushing's syndrome. The free DOC response to metyrapone in Cushing's syndrome due to adrenal adenoma was markedly different from that in patients with adrenal hyperplasia (pituitary-dependent) and may serve as a test to ascertain the etiology of the disorder. Correlations of free DOC and aldosterone excretion with free cortisol excretion, and their responses to the administration of metyrapone and dexamethasone were compatible with ACTH dependency in adrenal hyperplasia, autonomous production of steroids in adrenal adenomas and a chaotic steroidogenesis in adrenal carcinoma.