Cortisol is a glucocorticoid that is centrally involved in the regulation of metabolism of glucose and proteins. Its synthetic form is commonly referred to as hydrocortisone.
It is diabetogenic due to an increase in hepatic gluconeogenesis and an anti-insulin effect on the peripheral tissues. It is also required for catecholamine action, its deficiency preventing vasoconstriction.
It is produced from either of the other endogenous glucocorticoids, 11-deoxycortisol or cortisone.
Cortisol is excreted as various 17-oxogenic steroids and urinary free cortisol. The administration of metyrapone inhibits a step in cortisol synthesis and causes loss of normal negative feedback.
Raised urinary cortisol is of value as a screening test for Cushing's syndrome but not hypoadrenalism.
Last reviewed 01/2018