研究開発・学会発表

 

 

[Background & Purpose]

Studies have shown that carnitine levels in seminal plasma are positively correlated with sperm density and motility rate. However, whether a similar correlation exists in Japanese males remains to be determined. Here, we investigated seminal plasma carnitine concentration in Japanese men with normal and abnormal seminal parameters.
 
[Materials & Methods]

Sixty-nine Japanese men who were admitted to our clinic for semen analysis were included in the study after providing written consent. Patients were categorized into five groups according to the WHO laboratory manual 4th edition as follows: Group A, 25 men with normal findings; Group B, 17 men with oligozoospermia; Group C, 3 men with asthenozoospermia; Group D, 16 men with azoospermia with asthenozoospermia; and Group E, 9 men with azoospermia. Semen was stored at −20°C until carnitine measurement. Total carnitine concentration was measured by the absorbance rate using the oxidation-reduction enzyme reaction.

[Results]

Total carnitine levels (mean±SD) for groups A–E were 574.8 ± 276.4 μM, 326.1 ± 176.4 μM, 498.4 ± 279.7 μM, 398.7 ± 224.6 μM and 286.0 ± 149.6 μM, respectively.
Carnitine levels were significantly higher in Group A than in groups B, D and E. Total carnitine levels correlated positively with sperm density and motile sperm density (R=0.443 and R=0.424)

[Conclusions]  

Carnitine concentration in seminal plasma was associated with abnormal spermatogenesis in Japanese men. The correlation of carnitine with motile sperm concentration suggests that it plays a role in the pathogenesis of male infertility.