title: Increased production of 17beta-estradiol in endometriosis lesions is the result of impaired metabolism.
abstract: BACKGROUND
  substantial evidence suggests that the expression of steroid metabolizing enzymes in endometriosis is altered, turning the ectopic endometrium into a source of 17beta-estradiol. However, whether these differences result in a net increase in local 17beta-estradiol production/activity has not been shown.
  
  
  METHODS
  The activities of the most important steroidogenic enzymes synthesizing and inactivating 17beta-estradiol were determined by HPLC in matched eutopic and ectopic tissue from patients with endometriosis (n = 14) and in endometrium from controls (n = 20).
  
  
  RESULTS
  Aromatase activity is negligible in the ectopic endometrium, whereas the activity of estrogen sulfatase is high though not different between ectopic, eutopic and control endometrium. The activity of 17beta-hydroxysteroid dehydrogenases (17beta-HSDs) converting estrone into 17beta-estradiol is higher in the ectopic compared to the eutopic endometrium in patients. The activity of 17beta-HSDs converting 17beta-estradiol back to estrone is significantly lower in the ectopic compared to the eutopic endometrium of both patients and controls. To evaluate the net metabolic capacity of tissues to synthesize 17beta-estradiol, we calculated the activity ratio between 17beta-HSDs synthesizing versus 17beta-HSDs inactivating 17beta-estradiol. This ratio is significantly higher in the ectopic compared to the eutopic endometrium of patients and controls, indicating a high synthesis of 17beta-estradiol in the ectopic locations. This is further supported by the elevated mRNA levels of the estrogen-responsive gene TFF1 in all ectopic compared to eutopic endometria.
  
  
  CONCLUSIONS
  Endometriotic lesions have higher production of 17beta-estradiol than the eutopic endometrium of patients and controls. This is mostly the result of impaired metabolism.
authors.affiliation: GROW, School for Oncology and Developmental Biology, University Maastricht, and Department of Obstetrics and Gynecology, University Hospital Maastricht, 6202 AZ Maastricht, The Netherlands. b.delvoux@og.unimaas.nl
authors.forename: Bert
authors.initials: B
authors.lastname: Delvoux
authors.forename: Patrick
authors.initials: P
authors.lastname: Groothuis
authors.forename: Thomas
authors.initials: T
authors.lastname: D'Hooghe
authors.forename: Cleophas
authors.initials: C
authors.lastname: Kyama
authors.forename: Gerard
authors.initials: G
authors.lastname: Dunselman
authors.forename: Andrea
authors.initials: A
authors.lastname: Romano
mesh_terms: D015067:17-Hydroxysteroid Dehydrogenases / Q000378:metabolism; D004715:Endometriosis / Q000378:metabolism*; D004958:Estradiol / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D043266:Steryl-Sulfatase / Q000378:metabolism; D000071163:Trefoil Factor-1; D025521:Tumor Suppressor Proteins / Q000235:genetics
chemical_list: C051838:TFF1 protein, human; D000071163:Trefoil Factor-1; D025521:Tumor Suppressor Proteins; D004958:Estradiol; D015067:17-Hydroxysteroid Dehydrogenases; D043266:Steryl-Sulfatase