Cortisol is a hormone, related to the steroids, produced in the adrenal gland. It increases blood pressure and blood sugar levels, aids the metabolism of food, and suppresses the immune system and bone production. In a growing fetus, it aids development of the lungs. In addition to the treatment of Addison's, a pharmaceutical preparation of cortisol is used to treat arthritis and allergy. Hydrocortisone(TM) is the pharmaceutical preparation of cortisol