glucocorticoid

Glucocorticoids are a family of steroid hormones from the adrenal cortex whose name literally means glucose-cortex-steroid — a hint at their core job of raising blood sugar. The body's natural glucocorticoid is cortisol, but the term also covers a whole pharmacy of synthetic drugs like prednisone and dexamethasone that doctors use to calm inflammation. Think of them as the body's all-purpose stress and damage-control hormones.

Their effects are broad. Metabolically, glucocorticoids push the body to make glucose from protein and fat, ensuring fuel during stress or fasting. On the immune system, they are potently anti-inflammatory and immunosuppressive — they quiet overactive immune responses, which is why they treat asthma, autoimmune disease, and transplant rejection. They act by entering cells, binding the glucocorticoid receptor, and altering gene expression in nearly every tissue.

The flip side of their power is their toll. Long-term high levels — from a tumor, or far more commonly from taking glucocorticoid medication — cause the same picture as Cushing's syndrome and also suppress the body's own production by feeding back on the HPA axis. This is why such medications must be tapered slowly rather than stopped abruptly.