Seminal plasma alpha-glucosidase activity and male infertility

Measurement of alpha-glucosidase (alpha-GLUC) activity by means of a simplecolorimetric test using a commercial kit (EpiScreen; FertiPro, Lotenhulle,Belgium) yielded results that were strongly correlated with the valuesobtained for the neutral iso-enzyme measured by a fluorimetric referencemethod (r=0.85, P=0.003, n=13). The former method was characterized by alow intra- and inter-coefficient of variation (6.6 and 4.3% respectively).Vasectomized men with azoospermia (n=27) had a significantly loweralpha-GLUC activity in semen than vasectomized men with residualspermatozoa present (n=11, P < 0.01) and men with azoospermia of primarytesticular origin (n=33, P < 0.01). Receiver operating curve (ROC)analysis showed alpha-GLUC measurement to be reasonably accurate indifferentiation between cases with obstructive versus testicularazoospermia at criterion value 13.5 U/l (sensitivity=82%, specificity=70%). In cases with spermatozoa present, alpha-GLUC activity and output perejaculate were positively correlated with sperm concentration (r=0.53 and0.38, n=472), linear velocity (r=0.35 and 0.30, n=224), curvilinearvelocity (r=0.32 and r=0.29, n=224), semen adenosine triphosphate (r=0.35and 0.26, n=64), the concentration of 5alpha-dihydrotestosterone (r=0.31and 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 inverselycorrelated with ROS generation after 12-myristate, 13-acetate phorbol esterstimulation (r=-0.27, n=104), and both alpha-GLUC activity and total outputwere inversely correlated with the concentration of peroxidase- positivewhite blood cells among samples with > or =1x10(6)/ml of these cells(r=-0.30 and -0.19, n=165). It is concluded that simple photometricmeasurement of alpha-GLUC activity in seminal plasma reflects thefunctional state of the epididymis and may be helpful for the differentialdiagnosis of certain cases with azoospermia.