title: Effect of acute in vivo sildenafil citrate and in vitro 8-bromo-cGMP treatments on semen parameters and sperm function.
abstract: OBJECTIVE
  To determine the effect of acute in vivo sildenafil citrate (VIAGRA) and in vitro 8-Bromo-cGMP treatments on semen parameters and sperm function.
  
  
  METHODS
  Prospective double-blind, placebo-controlled, crossover, two-period clinical investigation.
  
  
  METHODS
  Healthy volunteers in an academic research environment.
  
  
  METHODS
  Twenty male volunteers with normal erectile function and normal electrocardiogram were recruited.
  
  
  METHODS
  In vivo: 50 mg of sildenafil citrate (VIAGRA) or placebo was administered p.o., and semen samples were collected 1 hour after administration of the test drug. In vitro: 8-Bromo-cGMP (20 microM; 60 minutes) was added to semen samples.
  
  
  METHODS
  Macroscopic and microscopic seminal parameters were measured and motility studies performed. Various acrosome reaction studies and sperm-zona pellucida binding studies were also done.
  
  
  RESULTS
  Either sildenafil citrate (VIAGRA) or 8-Bromo-cGMP treatments had no effect on both macroscopic and microscopic seminal parameters as well as the acrosome reaction. Sperm-zona pellucida binding results were however increased to 148.75% and 134%, respectively, by these treatments. Various kinematical parameters increased after treatment with the most significant increase detected in the population of rapid cells.
  
  
  CONCLUSIONS
  VIAGRA can be used successfully to enhance sperm motility and binding to the oocyte especially during fertility treatments.
authors.affiliation: University of Stellenbosch, Tygerberg, South Africa. ssdp@sun.ac.za
authors.forename: Stefan S
authors.initials: SS
authors.lastname: du Plessis
authors.forename: Paul S
authors.initials: PS
authors.lastname: de Jongh
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Franken
mesh_terms: D020101:Acrosome Reaction / Q000187:drug effects; D000328:Adult; D001696:Biomechanical Phenomena; D018592:Cross-Over Studies; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004311:Double-Blind Method; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D010726:Phosphodiesterase Inhibitors / Q000009:adverse effects / Q000494:pharmacology*; D010879:Piperazines / Q000009:adverse effects / Q000494:pharmacology*; D011687:Purines; D012661:Semen / Q000187:drug effects; D000068677:Sildenafil Citrate; D013081:Sperm Motility / Q000187:drug effects; D013084:Sperm-Ovum Interactions / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects* / Q000502:physiology*; D013450:Sulfones; D015044:Zona Pellucida / Q000502:physiology
chemical_list: D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; C016276:8-bromocyclic GMP; D000068677:Sildenafil Citrate; D006152:Cyclic GMP