3β-HSD VI

3β-Hydroxysteroid dehydrogenase type VI (3β-HSD VI, Hsd3b6) is a steroidogenic enzyme that catalyzes the conversion of Δ5-3β-hydroxysteroids into Δ4-ketosteroids and is required for the biosynthesis of active steroid hormones.^[1][2] Mechanistically, Hsd3b6 belongs to the NAD⁺-dependent dehydrogenase/isomerase group of murine 3β-HSD isoforms and participates in pathways controlling progesterone, aldosterone, and androgen production.^[2][3] In adrenal tissue, Hsd3b6 expression is highly restricted to aldosterone-producing zona glomerulosa cells, and experimental overexpression increases aldosterone synthesis, indicating a critical role in mineralocorticoid steroidogenesis.^[1] In reproductive tissues, Hsd3b6 is strongly detected in interstitial Leydig cells of the testis and is associated with testosterone-producing steroidogenic compartments.^[1] During early mouse pregnancy, 3β-HSD VI is the only identified 3β-HSD isoform expressed in decidual and giant trophoblast cells, where its expression correlates with progesterone biosynthesis and supports studies of fetomaternal immune regulation.^[2] Compared with related murine isoforms, Hsd3b6 displays marked tissue- and temporal-specific expression, distinguishing it from broadly expressed steroidogenic enzymes and supporting its use as an experimental marker of specialized steroidogenic cell populations.^[1][2] Isoform-specific antibodies against Hsd3b6 have enabled precise immunolocalization studies in adrenal gland, testis, skin, and placenta, providing practical tools for investigating tissue-specific steroidogenesis and endocrine regulation.^[1]