Inclusion Criteria:

• Age ≥18 years.

• Able to provide informed consent.

• No known or suspected adrenal disorder.

• No known or suspected pituitary or hypothalamic disorder.

• No glucocorticoid exposure of any kind for at least 3 months prior to testing, including oral, injectable, inhaled, topical high-potency, intra-articular, epidural, rectal, or ophthalmic glucocorticoids.

• No opioid therapy exceeding 20 morphine milligram equivalents per day.

• Willingness to take metyrapone at midnight with a snack and return for morning blood collection between 7:30 and 8:30 AM.

Exclusion Criteria:

• Known adrenal insufficiency, Cushing syndrome, mild autonomous cortisol secretion, primary aldosteronism, pheochromocytoma/paraganglioma, adrenal mass under active evaluation, congenital adrenal hyperplasia, or adrenal cancer.

• Known pituitary mass, pituitary hormone deficiency, prior pituitary surgery or radiation, or suspected hypothalamic-pituitary-adrenal axis disorder.

• Any glucocorticoid exposure within 3 months.

• Current oral contraceptive therapy or estrogen-containing hormonal therapy, because of effects on cortisol-binding globulin and interpretation of total cortisol concentrations.

• Pregnancy or breastfeeding.

• Current opioid therapy >20 MME/day.

• Known intolerance, allergy, or contraindication to metyrapone.

• Severe acute illness, unstable chronic illness, or recent hospitalization within 30 days.

• Use of medications judged by the investigator to interfere substantially with metyrapone metabolism, cortisol interpretation, or participant safety.

• Inability to comply with study procedures.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 07/15/2026. Questions regarding updates should be directed to the study team contact.