Figure 2.

Aldosterone biosynthesis pathway. Cholesterol is transported to the inner mitochondrial membrane, where it is hydroxylated and cleaved by cytochrome P450scc to produce pregnenolone. Pregnenolone is relocated to the membrane of smooth endoplasmic reticulum, where it is oxidized by HSB3D to produce progesterone. Eleven deoxycorticosterone is generated by CYP21-mediated hydroxylation of progesterone and moves back to the inner mitochondrial membrane, where it is subject to ADS-catalyzed sequential 11-hydroxylation, 18-hydroxylation, and 18-oxidation, producing corticosterone, 18-OH corticosterone, and finally aldosterone, respectively. P450scc, cytochrome P450 side chain cleavage enzyme; HSD3B, 3β-hydroxysteroid dehydrogenase; CYP 21, 21 hydroxylase; ADS, aldosterone synthase.