Carnitine and acylcarnitines in semen from azoospermic patients

Carnitine and its short-chain acyl esters were assayed in semen from normospermic and azoospermic men. Extremely low concentrations of free carnitine and acylcarnitine were found in semen from patients with obstructive azoospermia where the ejaculate was primarily of prostatic origin, and low values were also obtained in obstruction of the vas deferens, where the epididymal contents were not ejaculated. Semen from patients whose azoospermia was caused by testicular dysfunction had low acylcarnitine concentrations and normal levels of free carnitine in most cases, but a group of patients with severe testicular failure (including cases of Klinefelter syndrome and cryptorchidism) had lower semen free carnitine concentrations. Whereas treatment with human chorionic gonadotropin increased serum testosterone levels in azoospermic patients, it did not increase the free carnitine concentration in semen, although it increased the proportion of carnitine found in acylcarnitines.