Free L-carnitine in human seminal plasma.
It has often been suggested that determination of free L(-)-carnitine in seminal plasma may provide a good indication of epididymal function. However, there has been disagreement regarding the origin of L(-)-carnitine (epididymis and seminal vesicles) and its concentration in human seminal plasma. In this study, free L(-)-carnitine was determined after deproteinization with an enzymatic spectrophotometric method. In 29 semen samples from fathers and with normal spermiograms (semen volume between 2 and 6 ml, sperm count over 20.10(6)/ml, more than 50% motile spermatozoa), the total free L(-)-carnitine in the seminal plasma was 1010 nmoles (SD: +/- 480), in 16 samples from vasectomized men it was 131 nmoles (SD: +/- 77), and in 5 from men with agenesis of the vas deferens and seminal vesicles it was 21 nmoles (SD: +/- 25). These results suggest that free L(-)-carnitine in the seminal fluid is predominantly of epididymal origin. The results of free L(-)-carnitine determinations in split ejaculates and the absence of a correlation between L(-)-carnitine and fructose concentrations in semen from normal subjects indicate that the seminal vesicles make only on minor contribution to L(-)-carnitine in the seminal plasma.
D002331:Carnitine / Q000378:metabolism*; D006801:Humans; D008297:Male; D012661:Semen / Q000378:metabolism*; D012669:Seminal Vesicles / Q000002:abnormalities*; D013076:Sperm Count; D014649:Vas Deferens / Q000002:abnormalities*; D014659:Vasectomy
D002331:Carnitine