3 beta hydroxysteroid dehydrogenase / HSD3B1 and HSD3B2

Author: Nat Pernick, M.D. (see Authors page)

Revised: 2 September 2015, last major update July 2013

Copyright: (c) 2003-2015,, Inc.

PubMed Search: HSD3B1 and HSD3B2
  • Critical enzyme in biosynthesis of all steroid hormones; catalyzes conversions of progesterone from pregnenolone, 17-hydroxyprogesterone from 17-hydroxypregnenolone and androstenedione from dehydroepiandrosterone (Wikipedia)
  • Also called hydroxyl-δ-5-steroid dehydrogenase
  • Isomerase 1 (HSD3B1) localizes generally to placenta and nonsteroidogenic tissue; isomerase 2 (HSD3B2) generallly localizes to adrenal gland, gonads and steroidogenic tissue
  • Located on inner mitochondrial membrane; acts as both a dehydrogenase and an isomerase, due to a conformational change (Biochemistry 2011;50:11015)
  • Transcription in adrenal gland regulated by farnesoid X receptor (Mol Cell Endocrinol 2009;299:153)
  • Mutations cause rare form of congenital adrenal hyperplasia (Horm Res Paediatr 2012;77:334, Rev Med Liege 2004;59:485, Gene 2012;503:215)

Steroid synthesis chart

Uses by Pathologists
  • Identify adenocortical tissue origin (Arch Pathol Lab Med 2002;126:1118)
  • Note: fetal adrenal gland lacks 3 beta hydroxysteroid dehydrogenase
  • Confirm trophoblastic origin
Micro Images

3 beta-hydroxysteroid dehydrogenase immunohistology in adrenal gland

Adrenal gland zona fasciculata (fig B)

Placental villi

Placenta tissue showing
membrane and cytoplasmic

Positive Staining - Normal
Positive Staining - Disease
Negative Staining
  • Normal seminiferous tubules, fetal adrenal gland