18-Oxocortisol is a cortisol derivative generated by aldosterone synthase (CYP11B2). It acts as a naturally occurring mineralocorticoid agonist and serves as a biomarker in adrenal vein sampling.

Administration of 18-oxocortisol in rats triggers mineralocorticoid-type hypertension, characterized by hypokalemia, as well as enlargement of cardiac and renal tissues and cardiovascular lesions. Similarly, when administered to sheep, 18-oxocortisol leads to a swift elevation in blood pressure. Nonetheless, achieving an increase in blood pressure necessitates high doses[3].