Seminal carnitine content in obstructive azoospermia. Correlation with the anatomic level of obstruction.

Free carnitine in human semen originates predominantly in the epididymis. The role of carnitine in the evaluation of different forms of obstructive azoospermia was studied in 42 patients. In 14 of the men, a bilateral vasectomy had been performed. In the remaining 28 patients, the occlusion was located within the epididymis. In postvasectomy cases and where the occlusion was located in the cauda epididymidis, carnitine concentrations were low, with mean values of 115.57 mumol/l and 121.28 mumol/l, respectively. When the occlusion was located in the corpus epididymidis, the mean value increased to 194.72 mumol/l. In patients having obstruction of the caput epididymidis or of the rete testis, the mean value of free carnitine was 416.0 mumol/l. After vasovasostomy, a return of free carnitine concentration to the normal range was observed in 10 of 12 cases. The results indicate that there is a significant correlation in patients with obstructive azoospermia between the concentration of free carnitine and the anatomic site of the obstruction. These findings may lead to important conclusions concerning therapy and prognosis for patients presenting with this condition.