title: Sildenafil citrate improves sperm motility but causes a premature acrosome reaction in vitro.
abstract: OBJECTIVE
  To determine whether sildenafil citrate, a cyclic monophosphate-specific type 5 phosphodiesterase inhibitor, influences sperm motility or the acrosome reaction.
  
  
  METHODS
  Laboratory analysis of sperm motility after exposure to sildenafil citrate using computer-assisted semen analysis and acrosome reaction by fluorescein isothiocyanate-labeled peanut agglutinin staining.
  
  
  METHODS
  An assisted reproductive technology (ART) unit.
  
  
  METHODS
  Fifty-seven male patients.
  
  
  METHODS
  Sperm were divided into 90% (those with the best fertilizing potential used in assisted conception) and 45% (the poorer population) fractions by density centrifugation and incubated with sildenafil citrate (0.67 muM) at 37 degrees C for up to 180 minutes.
  
  
  METHODS
  Both the number and velocity of progressively motile sperm were significantly increased by sildenafil citrate between 15 and 135 minutes. Furthermore, samples revealed that these effects were consistent in the 90% and 45% populations of sperm. In both populations, sildenafil also caused a significant increase in the proportion of acrosome-reacted sperm-22.1% compared with 11.8% in the control group of the good quality fraction and 16.6% compared with 9.4% in the control group of the poorer quality fraction.
  
  
  CONCLUSIONS
  The use of sildenafil citrate may adversely affect male fertility.
authors.affiliation: School of Medicine, Obstetrics and Gynaecology, Queen's University Belfast, Institute of Clinical Science, Belfast, United Kingdom.
authors.forename: David R J
authors.initials: DR
authors.lastname: Glenn
authors.forename: Carmel M
authors.initials: CM
authors.lastname: McVicar
authors.forename: Neil
authors.initials: N
authors.lastname: McClure
authors.forename: Sheena E M
authors.initials: SE
authors.lastname: Lewis
mesh_terms: D020101:Acrosome Reaction / Q000187:drug effects* / Q000502:physiology; D000328:Adult; D006801:Humans; D007248:Infertility, Male / Q000139:chemically induced; D008297:Male; D010879:Piperazines / Q000009:adverse effects / Q000494:pharmacology*; D011687:Purines / Q000009:adverse effects / Q000494:pharmacology; D000068677:Sildenafil Citrate; D013081:Sperm Motility / Q000187:drug effects* / Q000502:physiology; D013450:Sulfones / Q000009:adverse effects / Q000494:pharmacology*
chemical_list: D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate