A study was initiated to determine the sources of carnitine in the male reproductive system. Free and total carnitine was measured in a group of healthy men before and after vasectomy. Each individual served as his own control. The results show that postvasectomy semen contains about 52% as much total carnitine and 40% as much free carnitine as prevasectomy samples. The data indicate that, in addition to the epididymis, the seminal vesicles and/or vas deferens are major contributors of carnitine in human semen.

Carnitine derivatives, including short‐chain acylcarnitines, were detected in human semen by a bioautographic method using a carnitine requiring mutant of the yeast, Torulopsis bovina. Acylcarnitines formed approximately 55% of the total carnitine content of semen from fertile males, whereas the acylcarnitine fraction of semen from infertile males comprised only 25%, and that of postvasectomy semen comprised 65%. Gas chromatographic analysis of the fatty acids liberated from acylcarnitine derivatives demonstrated the presence of acetyl, propionyl, isobutyryl, butyryl, and isovaleryl derivatives in postvasectomy semen and semen from fertile and infertile males.