Category: biosynthesis
Adrenal cortex + gonad pathway converting cholesterol to glucocorticoids / mineralocorticoids / androgens / estrogens. Rate-limiting: cholesterol side-chain cleavage by CYP11A1 (P450scc; StAR-mediated cholesterol import) → pregnenolone. Branch points: 17α-hydroxylase (CYP17A1) — glucocorticoid + androgen path; aldosterone synthase (CYP11B2) — mineralocorticoid path; aromatase (CYP19A1) — androgen → estrogen. Drug targets: ketoconazole + abiraterone block CYP17A1 (high-dose ketoconazole and abiraterone for castration-resistant prostate cancer); aromatase inhibitors (anastrozole / letrozole / exemestane) block CYP19A1 for ER+ breast cancer; metyrapone blocks 11β-hydroxylase (Cushing diagnostic). 21-hydroxylase deficiency (CYP21A2) is most common congenital adrenal hyperplasia.