Mechanisms of excessive estrogen formation in endometriosis

Serdar E. Bulun*, Bilgin Gurates, Zongjuan Fang, Mitsutoshi Tamura, Siby Sebastian, Jianfeng Zhou, Sanober Amin, Sijun Yang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

82 Scopus citations


Estrogen is produced in a number of human tissues including the ovary, placenta and extraglandular sites such as adipose tissue, skin and the brain. Aromatase is the key enzyme that regulates estrogen formation in these tissues. Aromatase activity is not detectable in normal endometrium. In contrast, aromatase is expressed aberrantly in endometriosis and is stimulated by PGE2. This results in local production of estrogen, which induces PGE2 formation and establishes a positive feedback cycle. Another abnormality in endometriosis, i.e. deficient 17β-hydroxysteroid dehydrogenase (17β-HSD) type 2 expression, impairs the inactivation of estradiol to estrone. These molecular aberrations collectively favor accumulation of increasing quantities of estradiol and PGE2 in endometriosis. The clinical relevance of these findings was exemplified by the successful treatment of an unusually aggressive case of postmenopausal endometriosis using an aromatase inhibitor.

Original languageEnglish (US)
Pages (from-to)21-33
Number of pages13
JournalJournal of Reproductive Immunology
Issue number1-2
StatePublished - 2002


  • 17β-Hydroxysteroid dehydrogenase type 2
  • Aromatase
  • Aromatase inhibitor
  • Cyclo-oxygenase
  • Endometriosis
  • Estrogen
  • Estrogen biosynthesis
  • Estrogen metabolism
  • Osteoporosis
  • Progesterone
  • Prostaglandin E
  • Steroidogenesis

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Reproductive Medicine
  • Obstetrics and Gynecology


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