Epididymis and seminal vesicle as sources of carnitine in human seminal fluid: the clinical significance of the carnitine concentration in human seminal fluid

Carnitine determinations in human seminal fluid were shown to be useful in assessing epididymal and seminal vesicle function and in locating blockages in the male reproductive tract. The carnitine concentrations in 50 samples of seminal fluid ranged from 15 to 530 μg/ml (as carnitine HCl). The patients could be divided into 4 classes. Patients with normal seminal vesicle and epididymal function had values of 250 μg/ml or above. Those with a defective epididymis and a functional seminal vesicle had intermediate carnitine levels (100 to 200 μg/ml) and normal fructose values in the seminal fluid. Patients with a defective seminal vesicle but a functional epididymis had intermediate carnitine concentrations and low fructose levels. Extremely low carnitine values (less than 100 μg/ml) were found in seminal fluid from patients whose epididymis and seminal vesicle both were defective. The possible role of carnitine in sperm maturation was discussed.