Alpha-1,4-glucosidase activity and the presence of germinal epithelium cells in the semen for differential diagnosis of obstructive and nonobstructive azoospermia.

Among azoospermics, the activity of seminal alpha-glucosidase (alpha G) is low in obstruction (OBS) cases, but there is no agreement regarding its value in others. With the hypothesis that a more marked decrease in alpha G activity occurs in OBS than in spermatogenesis arrest (SA), the enzyme was measured in the following groups: (1) vasectomized males (n = 15), (2) azoospermics with OBS (n = 7), (3) azoospermics with SA (n = 11), and (4) fertile males (n = 15). Patients within groups 2 and 3 had a testicular volume > or = 15 mL, no clinical evidence of abnormal epididymis, normal serum gonadotropins, and histological diagnosis. alpha G activities (mU/g protein, means +/- SD) by group were (1) 131 +/- 60, (2) 312 +/- 186, (3) 728 +/- 303, and (4) 1176 +/- 374. All between-group differences were significant (t test, p < .01), except for groups 1 vs. 2 comparison (.05 > p > .01). These results support the notion that SA is associated with a decrease in alpha G that is less marked that seen in OBS. The search for germinal epithelium cells in semen also allows discrimination between these two azoospermic groups.