title: The impact of testosterone, tibolone and black cohosh on purified mammary and placental 17β-hydroxysteroid dehydrogenase type 1.
abstract: BACKGROUND
  Mammary and placental 17β-hydroxysteroid dehydrogenase type 1 (17βHSD1).
  
  
  OBJECTIVE
  To assess the impact of testosterone, tibolone, and black cohosh on purified mammary and placental 17βHSD1.
  
  
  METHODS
  17βHSD1 was purified from human mammary gland and placenta by column chromatography, its activity was monitored by a radioactive activity assay, and the degree of purification was determined by gel electrophoresis. Photometric cofactor transformation analysis was performed to assess 17βHSD1 activity without or in presence of testosterone, tibolone and black cohosh.
  
  
  RESULTS
  17βHSD1 from both sources displayed a comparable basal activity. Testosterone and tibolone metabolites inhibited purified mammary and placental 17βHSD1 activity to a different extent, whereas black cohosh had no impact.
  
  
  CONCLUSIONS
  Studies on purified enzymes reveal the individual action of drugs on local regulatory mechanisms thus helping to develop more targeted therapeutic intervention.
  
  
  CONCLUSIONS
  Testosterone, tibolone and black cohosh display a beneficial effect on local mammary estrogen metabolism by not affecting or decreasing local estradiol exposure.
authors.affiliation: Department of Obstetrics and Gynecology, Inselspital Bern , Bern , Switzerland .
authors.forename: Petra
authors.initials: P
authors.lastname: Stute
authors.forename: Kathrin
authors.initials: K
authors.lastname: Kalkhake
authors.forename: Ludwig
authors.initials: L
authors.lastname: Kiesel
authors.forename: Martin
authors.initials: M
authors.lastname: Götte
mesh_terms: D015067:17-Hydroxysteroid Dehydrogenases / Q000037:antagonists & inhibitors* / Q000302:isolation & purification / Q000378:metabolism; D001940:Breast / Q000201:enzymology / Q000378:metabolism; D031885:Cimicifuga / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D005260:Female; D006801:Humans; D015394:Molecular Structure; D009652:Norpregnenes / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D010920:Placenta / Q000201:enzymology / Q000378:metabolism; D011247:Pregnancy; D013329:Structure-Activity Relationship; D013739:Testosterone / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D004791:Enzyme Inhibitors; D009652:Norpregnenes; D013739:Testosterone; D015067:17-Hydroxysteroid Dehydrogenases; C044256:3 (or 17)-beta-hydroxysteroid dehydrogenase; C027385:tibolone
keywords: 17βHSD1; Black cohosh; mammary gland; placenta; testosterone; tibolone