Epididymal markers in human infertility.

Alpha-glucosidase, glycerophosphocholine, and L-carnitine were measured in sperm-free seminal plasma to determine whether these markers reflected the epididymal function of men attending an infertility clinic. The putative markers correlated well with each other (r = 0.66 to 0.70) and in 92% of 283 cases were accurate in categorizing semen as containing normal or subnormal amounts of markers. Glucosidase was considered the best index of epididymal function and was used for a further 306 samples. The ejaculate content of epididymal markers was correlated with testicular volume and serum testosterone below values of 30 ml and 30 nmol/l, respectively. Markers were also correlated with the concentration and motility of spermatozoa in semen. Seventy-one of 425 patients (17%) displayed subnormal epididymal secretions, mainly in association with hypogonadism (Klinefelter syndrome, Kallman syndrome, idiopathic hypogonadotropic hypogonadism) but also in cases of obstructed ducts, maldescended testicles, and local irradiation following hemicastration. Because azoospermic patients had reduced epididymal markers with both high and low FSH levels and a large proportion of men with reduced glucosidase and normal FSH suffered from testicular failure, it is suggested that other indices of testicular function are required for correct interpretation of reduced epididymal markers. Thirteen patients (3%) had low markers for which no cause was apparent; these may be cases of infertility due to isolated epididymal dysfunction.