title: [Level of free L-carnitine in human seminal plasma and its correlation with semen quality].
abstract: OBJECTIVE
  To evaluate the difference of the free L-carnitine level in seminal plasma between fertile and infertile men and the correlation of free L-carnitine with semen quality, and to study the effect of L-carnitine on male fertility and its role in the evaluation and treatment of male infertility.
  
  
  METHODS
  Semen samples of 230 infertile (normozoospermia, n=117, oligozoospermia, n=81, azoospermia, n=32) and 30 fertile men were collected and the level of free L-carnitine in seminal plasma and such sperm parameters as sperm concentration, motility and vitality, were determined by high performance liquid chromatography and computer-assisted semen analysis system, respectively. The results were analyzed with the SPSS 12.0 software.
  
  
  RESULTS
  The level of free L-carnitine in the seminal plasma of the fertile men was significantly higher than that of the infertile (P < 0.01). The lower the sperm concentration, the weaker the sperm vitality, the more significant the difference. The level of free L-carnitine in the semen was positively correlated with sperm concentration (r = 0.521, P < 0.001), and sperm motility (r = 0.319, P < 0.001) and vitality (r = 0.251, P < 0.001).
  
  
  CONCLUSIONS
  The level of free L-carnitine in seminal plasma, significantly correlated with sperm concentration, motility and vitality, can be taken as a biochemical index used as a guidance for the clinical treatment of male infertility as well as for the study on the mechanisms of male reproduction.
authors.affiliation: PLA Institute of Clinical Laboratory Medicine, Nanjing General Hospital of Nanjing Command, PLA , Nanjing, Jiangsu 210002, China. liker1017@163.com
authors.forename: Ke
authors.initials: K
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Yu-feng
authors.initials: YF
authors.lastname: Huang
authors.forename: Xue-jun
authors.initials: XJ
authors.lastname: Shang
mesh_terms: D000328:Adult; D002331:Carnitine / Q000032:analysis*; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007248:Infertility, Male / Q000503:physiopathology*; D008297:Male; D012661:Semen / Q000737:chemistry*; D013076:Sperm Count; D013081:Sperm Motility
chemical_list: D002331:Carnitine