THE EFFECT OF SOME PROTEINASE-INHIBITORS ON LIQUEFACTION OF HUMAN SEMEN

This study examined the effect of some proteinase inhibitors on liquef action of human semen. It revealed that a strong plasmin inhibitor, 6- amidino-2-naphtyl-6-guanidinobenzoate dihydrochloride (Fusan) showed a significant inhibition of liquefaction, while t-amino caproic acid (t -ACA) showed a weak retardation effect. In terms of sperm quality afte r liquefaction, Fusan (10 mM), ethyl diamine tetra-acetic acid (EDTA) and Urinastatin completely inhibited sperm motility. Fusan (1 mM) and Lima bean trypsin inhibitor (LBTI) decreased sperm motility significan tly, while leupeptin and t-ACA had little effect. Leupeptin, LBTI, t-A CA and Fusan (1 mM) did not affect sperm speed. 50% inhibition of sper m motility was calculated to be similar to 1.7 mM of Fusan concentrati on. In addition, two inhibitors, Chymostatin and Phosphoramidon were a lso tested with each experiment and had no effect on liquefaction or o n sperm motility and speed. These results strongly suggest that plasmi n may play an important role in the liquefaction process of human seme n.