Alpha-glucosidase as a specific epididymal enzyme marker. Its validity for the etiologic diagnosis of azoospermia.

Azoospermic semen was obtained from 39 vasectomized men and 93 patients consulting for infertility. The latter underwent bioclinical investigations including measurement of plasma FSH and testicular biopsies. Carnitine content and alpha-glucosidase activity in semen samples were measured. The activity of alpha-glucosidase was determined systematically by a semiquantitative microtechnique and was verified by a spectrophotometric assay. A positive correlation was observed between carnitine and alpha-glucosidase activity. Both parameters were severely diminished in semen from the vasectomized men and the patients suffering from a complete obstruction of the genital tract. Enzyme activity was the most discriminant parameter in terms of sensitivity and specificity. The measurement of alpha-glucosidase in semen is a simple and sensitive method for determining the origin of azoospermia when used in conjunction with assays for plasma FSH.