Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte levels, and behavior.

• Glucocorticoids such as cortisol control carbohydrate, fat and protein metabolism and are anti-inflammatory by preventing phospholipid release, decreasing eosinophil action and a number of other mechanisms.
• Mineralocorticoids such as aldosterone control electrolyte and water levels, mainly by promoting sodium retention in the kidney.

Some common natural hormones are corticosterone (C₂₁H₃₀O₄), cortisone (C₂₁H₂₈O₅, 17-hydroxy-11-dehydrocorticosterone) and aldosterone.

Biosynthesis

Aldosterone and corticosterone share the first part of their biosynthetic pathway. The last part is either mediated by the aldosterone synthase (for aldosterone) or by the 11β-hydroxylase (for corticosterone). These enzymes are nearly identical (they share 11β-hydroxylation and 18-hydroxylation functions). But aldosterone synthase is also able to perform an 18-oxidation. Moreover, aldosterone synthase is found within the zona glomerulosa at the outer edge of the adrenal cortex; 11β-hydroxylase is found in the zona fasciculata and reticularis.

Uses

Synthetic drugs with corticosteroid-like effect are used in a variety of conditions, ranging from brain tumors to skin diseases. Dexamethasone and its derivatives are almost pure glucocorticoids, while prednisone and its derivatives have some mineralocorticoid action in addition to the glucocorticoid effect. Fludrocortisone (Florinef) is a synthetic mineralocorticoid. Hydrocortisone (cortisol) is available for replacement therapy, e.g. in adrenal insufficiency and congenital adrenal hyperplasia.

Synthetic glucocorticoids are used in the treatment of joint pain or inflammation (arthritis), temporal arteritis, dermatitis, allergic reactions, asthma, hepatitis, systemic lupus erythematosus, inflammatory bowel disease (ulcerative colitis and Crohn's disease), sarcoidosis and for glucocorticoid replacement in Addison's disease or other forms of adrenal insufficiency. Topical formulations for treatment of skin, eye diseases (uveitis) or inflammatory bowel disease are available. Corticosteroids are also used supportively to prevent nausea, often in combination with 5-HT3 antagonists (e.g. ondansetron).