Aldosterone is the primary mineralocorticoid. Aldosterone is synthesized and secreted in response to renin-angiotensin system activation or high dietary potassium by the zona glomerulosa of the adrenal cortex.
21-Deoxycortisol is a corticosteroid metabolite of 17-hydroxyprogesterone produced in the adrenal glandvia11-hydroxylation by 11β-hydroxylase.1,2Serum levels of 21-deoxycortisol are elevated in patients with congenital adrenal hyperplasia that are heterozygous for mutations inCYP2A21, the gene encoding steroid 21-hydroxylase, and have been used as a biomarker for the detection of 21-hydroxylase deficiencies.
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.