Cortisol
Cortisol is a steroid hormone made by the adrenal cortex. It helps regulate metabolism, immune activity, and the body’s response to stress.
Hypothalamic–pituitary–adrenal axis: The hormonal system linking the hypothalamus, pituitary gland, and adrenal glands in stress regulation. This axis controls cortisol production through signals from the brain to the adrenal cortex.
Adrenal cortex: The outer region of the adrenal gland that produces steroid hormones. Its zona fasciculata is the principal source of circulating cortisol.
Cushing syndrome: A disorder caused by prolonged exposure to excessive glucocorticoids, including cortisol. It illustrates the effects of chronically high cortisol exposure.
Gluconeogenesis: The production of glucose from noncarbohydrate precursors, mainly in the liver. Cortisol supports glucose availability partly by promoting this process.
Aldosterone: A mineralocorticoid hormone that regulates sodium balance, potassium excretion, and blood volume. Both are adrenal cortex steroids, but aldosterone primarily controls salt and water balance.
Adrenocorticotropic hormone: A pituitary hormone that stimulates the adrenal cortex to produce cortisol and other steroids. ACTH is the immediate hormonal signal that prompts cortisol secretion.
Steroid hormone: A hormone synthesized from cholesterol that can cross cell membranes and bind intracellular receptors. Cortisol’s chemical structure places it in this hormone family.
Addison disease: A condition in which the adrenal cortex fails to produce enough hormones, including cortisol. Low cortisol production in this disorder contrasts with cortisol excess.
Immune system: The cells, tissues, and molecules that defend the body against infection and other threats. Cortisol modulates immune activity and can suppress inflammation.
Cortisone: A less active glucocorticoid that can be converted to cortisol in some tissues. Cortisone is closely related to cortisol but has weaker glucocorticoid activity.