Human steroids are produced by the adrenal gland and are under the direct or indirect control of the hypothalamus, pituitary, and adrenal glands. The two major classes of steroids that have significant clinical metabolic effects are the glucocorticoids (mainly cortisol), which regulate glucose and other anabolic cascades, and the mineralocorticoids (mainly aldosterone), which handle Na–K equilibrium.

Patients can become deficient in steroid production through primary Addison’s disease (e.g., adrenal cortex destruction, hemorrhage) or secondary Addison’s disease (e.g., through a deficiency of corticotropin or adrenocorticotropic hormone [ACTH] or through exogenous steroid administration). Primary Addison’s disease is rare, but secondary Addison’s disease is not uncommon. Exogenous glucocorticoids are used in a variety of diseases including organ and bone transplants, rheumatoid arthritis, systemic lupus erythematosus and other collagen vascular disorders, psoriasis, chronic obstructive pulmonary disease, inflammatory bowel disease, and many hematological diseases such as idiopathic thrombocytopenic purpura (ITP).