18-hydroxycorticosterone

18-Hydroxycorticosterone is an endogenous steroid. It is a derivative of corticosterone.

==Function== thumb|left|560px|Corticosteroid biosynthetic pathway in rat18-Hydroxycorticosterone serves as an intermediate in the synthesis of aldosterone by the enzyme aldosterone synthase in the zona glomerulosa. It is also an intermediate in the biosynthesis of corticosterone. It spontaneously and reversibly converts to various less polar forms and derivatives, some of which serve as precursors to aldosterone or corticosterone. Specifically, 21-hydroxy-11,18-oxido-4-pregnene-3,20-dione (18-DAL) is hydroxylated to aldosterone in the presence of malate and NADP+ at pH 4.8, indicating that 18-DAL acts as a metabolic intermediate between 18-hydroxycorticosterone and aldosterone. Corticosterone is a mediate precursor in this biosynthesis pathway, with 18-hydroxycorticosterone serving as an intermediate between corticosterone and aldosterone.