Tests Case II-2 Case II-4 Case III-2 Case III-7 Case III-4 Baseline plasma cortisol level (µg/dL)           0800 h (normal range, 9-23) 37.9 26.1 17.5 17.3 5.32 1600-2200 h (normal range, 3-13) 33.8 20.4 19.0 14.1   Baseline 24-h urinary free cortisol level (µg/24-h) (normal range, 34-122) 1008 786 952     Baseline plasma ACTH level (pg/mL) 5.10 8.29 2.05 14.6 42.1 0800 h (normal range, 9-52)           Overnight low-dose dexamethasone suppression test*           Plasma cortisol level at 0800 h 32.3 24.3 20.9 13.8 4.57 Two-day low-dose dexamethasone suppression test**           Plasma cortisol level at 0800 h 36.9 20.1 17.3     24-h urinary free cortisol level 1162 762 1066     Overnight high-dose dexamethasone suppression test§           Plasma cortisol level at 0800 h       18.3   Two-day high-dose dexamethasone suppression test§§           Plasma cortisol level at 0800 h 33.7 20.0 22.9     24-h urinary free cortisol level 1470 676 1489

Table 1: Endocrinological studies (before adrenalectomy) in the five patients with primary pigmented nodular adrenocortical disease. *Overnight low-dose dexamethasone suppression test: 1 mg dexamethasone orally at 2300 h and blood sampling for cortisol level the following morning at 0800 h. ** Two-day low-dose dexamethasone suppression test: 0.5 mg dexamethasone orally every 6 h for 2 days and blood sampling for cortisol level at 0800 h on the third day of testing. Collecting 24-h urine for free cortisol level from 0800 h on the second day to 0800 h on the third day after dexamethasone administration. §Overnight high-dose dexamethasone suppression test: 8 mg dexamethasone orally at 2300 h and blood sampling for cortisol level the following morning at 0800 h. §§Two-day high-dose dexamethasone suppression test: 2 mg dexamethasone orally every 6 h for 2 days and blood sampling for cortisol level at 0800 h on the third day of testing. Collecting 24-h urine for free cortisol level from 0800 h on the second day to 0800 h on the third day after dexamethasone administration.