Activity and inhibition of 3-beta-hydroxysteroid dehydrogenase/delta-5-4-lsomerase in human skin

István Tóth, Mihály Szécsi, János Julesz, Imre Faredin

Research output: Contribution to journalArticle

12 Citations (Scopus)


Activity and inhibition of 3²-hydroxysteroid dehydrogenase/ Δ5-4-isomerase, a key enzyme of biosynthesis of androgenic steroids, in human skin were studied. Whole-width dermal tissue specimens excised from various regions of the male and female body were investigated with an in vitro radioenzyme assay method using dehydroepiandrosterone as substrate. The Michaelis-Menten constant of the enzyme was found to be Km=10 nM and the maximal velocity was Vmax = 0.625 pmol produced 4-androstene-3,17-dione/mg protein/20 min. Activity of 3²-hydroxysteroid dehydrogenase/Δ5-4-isomerase in male inguinal skin (n = 8) was 0.132-0.412, in female abdominal skin (n = 4) 0.140-0.255, in perineal skin (n = 4) 0.138-0.962 pmol/mg protein/20 min. The synthetic steroids cyproterone acetate, 4-MA and epostane proved to be potent inhibitors, IC50 values were 150, 6.2 and 1.45nM, respectively.

Original languageEnglish
Pages (from-to)160-168
Number of pages9
JournalSkin Pharmacology and Physiology
Issue number3
Publication statusPublished - Jan 1 1997


  • Androgen activity
  • Enzymes
  • Human skin
  • Inhibitors

ASJC Scopus subject areas

  • Physiology
  • Pharmacology
  • Dermatology

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