People interested in participating in this 3-day inpatient study will first undergo a physical exam and provide a blood sample to determine eligibility. Eligible participants will be admitted to the study site in the morning on the first study day. A blood sample will be taken and participants will receive one 10-mg pill of hydrocortisone. Heart rates and blood pressures will be taken every 4 hours throughout the day. In the morning of Day 2, a blood sample will be taken and participants will be asked to urinate in the toilet. After this point and until the end of the study, participants will collect all urine in a jug. On the morning of Day 3, participants will complete urine collection and a blood sample will be taken. Participants will then receive intravenously a medicine called cosyntropin, a synthetic form of a hormone that the body makes. About 1 hour after this, participants will provide a final blood sample. Participants will receive one last pill of hydrocortisone prior to the end of the study.