title: Mechanism of salutary effects of finasteride on post-traumatic immune/inflammatory response: upregulation of estradiol synthesis.
abstract: OBJECTIVE
  The aim of this study was to evaluate whether pretreatment with finasteride, a 5alpha-reductase inhibitor, improves immune functions after trauma-hemorrhage.
  
  
  BACKGROUND
  A number of studies have provided evidence for a gender dimorphism in host defense after trauma. Under stress conditions, such as trauma-hemorrhage, androgenic hormones have immunosuppressive effects, leading to increased susceptibility to sepsis, morbidity, and mortality. Testosterone is converted by 5alpha-reductase to 5alpha-dihydrotestosterone (DHT), a more potent androgen.
  
  
  METHODS
  Male C3H/HeN mice (8-10 weeks) were randomly assigned to receive finasteride or vehicle for 2 days and were then subjected to trauma-hemorrhage or sham operation. Trauma-hemorrhage was induced by a midline laparotomy and approximately 90 minutes of hemorrhagic shock (blood pressure, 35 mm Hg), followed by fluid resuscitation. Animals were killed 2 hours after resuscitation or sham procedure. Plasma levels and Kupffer cell production of cytokines (TNF-alpha, IL-6, IL-10, MCP-1, KC, and MIP-1alpha), lung neutrophil infiltration, and edema were evaluated.
  
  
  RESULTS
  Finasteride administration prevented the increase in cytokine plasma levels, decreased DHT, and increased 17beta-estradiol plasma concentrations. In addition, neutrophil infiltration and edema formation in the lung were reduced by finasteride. The salutary effects of finasteride were abrogated after coadministration with an estrogen receptor inhibitor (ICI 182,780). Increased Kupffer cell cytokine production normally observed after trauma-hemorrhage was prevented by treatment with finasteride.
  
  
  CONCLUSIONS
  These results suggest that inhibition of 5alpha-reductase leads to the conversion of testosterone to 17beta-estradiol, which produces salutary effects on the post-traumatic immune response.
authors.affiliation: Center for Surgical Research and Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama 35294-0019, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Frink
authors.forename: Ya-Ching
authors.initials: YC
authors.lastname: Hsieh
authors.forename: Shunhua
authors.initials: S
authors.lastname: Hu
authors.forename: Chi-Hsun
authors.initials: CH
authors.lastname: Hsieh
authors.forename: Hans-Christoph
authors.initials: HC
authors.lastname: Pape
authors.forename: Mashkoor A
authors.initials: MA
authors.lastname: Choudhry
authors.forename: Martin G
authors.initials: MG
authors.lastname: Schwacha
authors.forename: Kirby I
authors.initials: KI
authors.lastname: Bland
authors.forename: Irshad H
authors.initials: IH
authors.lastname: Chaudry
mesh_terms: D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000097:blood*; D058891:5-alpha Reductase Inhibitors; D000818:Animals; D016207:Cytokines / Q000097:blood*; D004791:Enzyme Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D004958:Estradiol / Q000097:blood*; D018120:Finasteride / Q000494:pharmacology / Q000627:therapeutic use*; D007728:Kupffer Cells / Q000187:drug effects / Q000502:physiology; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D020556:Neutrophil Infiltration / Q000187:drug effects / Q000502:physiology; D011654:Pulmonary Edema / Q000097:blood / Q000209:etiology / Q000517:prevention & control; D012771:Shock, Hemorrhagic / Q000097:blood / Q000276:immunology / Q000517:prevention & control*
chemical_list: D058891:5-alpha Reductase Inhibitors; D016207:Cytokines; D004791:Enzyme Inhibitors; D004958:Estradiol; D018120:Finasteride; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase