title: Mutual interaction of 17beta-estradiol and progesterone: electron emission. Free radical effect studied by experiments in vitro.
abstract: BACKGROUND
  Based on the different behaviour of 17beta-estradiol (17betaE(2)) and progesterone (PRG), it was of interest to investigate the interaction of both hormones in respect of their electron emission and cytotoxicity by experiments in vitro.
  
  
  METHODS
  The studies include determination of emitted electrons (e(-)(aq)) by the individual hormones as well as by their mixtures, all complexed with cyclodextrin (HBC). Experiments in vitro (Escherichia coli bacteria) were performed for a better understanding of the mechanisms involved. Survival ratios, DeltaD(37)(Gy), were calculated.
  
  
  RESULTS
  Aqueous HBC as well as 17betaE(2) and PRG, individually as well as in mixtures, are able to emit e(-)(aq). The resulting transients can lead to the formation of metabolites, some of which can initiate cancer. It was established that both hormones, 17betaE(2) and PRG, interact in respect to their electron emission property. In the frame of experiments in vitro, it was found that oxidizing radicals (OH, O(2)(-)) lead to negative DeltaD(37)(Gy) values, indicating cytostatic properties. On the other hand, the primary reducing radicals (e(-)(aq), H) lead to positive DeltaD(37)(Gy) values, indicating a radical-scavenging effect.
  
  
  CONCLUSIONS
  The main outcome of this work is that PRG in combination with 17betaE(2) can strongly reduce the number of carcinogenic 17betaE(2)-metabolites. This fact offers a new pathway for application of hormones in medical treatment of patients.
authors.affiliation: Section of Radiation Biology, Faculty of Life Sciences, University of Vienna, Althanstr. 14, UZA II, A-1090 Vienna, Austria. nikola.getoff@univie.ac.at
authors.forename: Nikola
authors.initials: N
authors.lastname: Getoff
authors.forename: Heike
authors.initials: H
authors.lastname: Schittl
authors.forename: Johannes
authors.initials: J
authors.lastname: Hartmann
authors.forename: Marion
authors.initials: M
authors.lastname: Gerschpacher
authors.forename: Shaobin
authors.initials: S
authors.lastname: Ying
authors.forename: Iren
authors.initials: I
authors.lastname: Danielova
authors.forename: Johannes C
authors.initials: JC
authors.lastname: Huber
mesh_terms: D000332:Aerobiosis; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D003505:Cyclodextrins / Q000494:pharmacology*; D004583:Electrons; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D004958:Estradiol / Q000378:metabolism / Q000494:pharmacology*; D005609:Free Radicals / Q000378:metabolism*; D007700:Kinetics; D010084:Oxidation-Reduction; D011374:Progesterone / Q000378:metabolism / Q000494:pharmacology*; D014466:Ultraviolet Rays
chemical_list: D003505:Cyclodextrins; D005609:Free Radicals; D011374:Progesterone; D004958:Estradiol