Measurement of alpha-glucosidase (alpha-GLUC) activity by means of a s
imple colorimetric test using a commercial kit (EpiScreen(R); FertiPro
, Lotenhulle, Belgium) yielded results that were strongly correlated w
ith the values obtained for the neutral iso-enzyme measured by a fluor
imetric reference method (r = 0.85, P = 0.003, n = 13), The former met
hod was characterized by a low intra-and inter-coefficient of variatio
n (6.6 and 4.3% respectively), Vasectomized men with azoospermia (n =
27) had a significantly lower alpha-GLUC activity in semen than vasect
omized men with residual spermatozoa present (n = 11, P < 0.01) and me
n with azoospermia of primary testicular origin (n = 33, P < 0.01), Re
ceiver operating curve (ROC) analysis showed alpha-GLUC measurement to
be reasonably accurate in differentiation between cases with obstruct
ive versus testicular azoospermia at criterion value 13.5 U/l (sensiti
vity = 82%, specificity = 70%), In cases with spermatozoa present, alp
ha-GLUC activity and output per ejaculate were positively correlated w
ith sperm concentration (r = 0.53 and 0.38, n = 472), linear velocity
(r = 0.35 and 0.30, n = 224), curvilinear velocity (r = 0.32 and r = 0
.29, n = 224), semen adenosine triphosphate (r = 0.35 and 0.26, n = 64
), the concentration of 5 alpha-dihydrotestosterone (r = 0.31 and 0.29
, n = 74), and gamma-glutamyltransferase activity (r = 0.62 and 0.32,
n = 275) in seminal plasma. The activity of alpha-GLUC was inversely c
orrelated with ROS generation after 12-myristate, 13-acetate phorbol e
ster stimulation (r = -0.27, n = 104), and both alpha-GLUC activity an
d total output were inversely correlated with the concentration of per
oxidase-positive white blood cells among samples,vith greater than or
equal to 1x10(6)/ml of these cells (r = -0.30 and -0.19, n = 165), It
is concluded that simple photometric measurement of alpha-GLUC activit
y in seminal plasma reflects the functional state of the epididymis an
d may be helpful for the differential diagnosis of certain cases with
azoospermia.