6β-hydroxycortisol excretion in hypercortisolemic states

Urinary 6/3-hydroxycortisol (6β-OHF) excretion was measured and compared with free cortisol and 17-hydroxycorticosteroid (17OH) excretion in normal children, patients with Cushing's syndrome or disease (CSD), and patients during cortisol therapy. Normal 6/JOHF excretion in children was 0.23 ± 0.03 mg/m²/24 h (mean ± SE). NO sex difference was found. ACTH infusion (40 U/day for 5 days) and high dose cortisol altered the 6β-OHF:17OH ratio so that it was indistinguishable from the ratio seen in CSD. The fact that both Cushing's disease and high dose cortisol therapy caused the same change in the 6β-OHF:17OH ratio suggests that cortisol and not ACTH induced 6 β -hydroxylase in hypercortisolemic subjects. Since the 6β-OHF: 17OH ratio in CSD patients was always well above the normal range, measurement of 6β-OHF excretion was a better and more rapid test for chronic hypercortisolemia than urinary 17OH or free cortisol. Thus, measurement of urinary 6β-OHF is suggested as a good diagnostic test for hypercortisolemic states.