[The influence of various molecules on the occurrence of the human sperm acrosome reaction]

The acrosome reaction is essential for fertilization, but the mechanism of the acrosome reaction of human spermatozoa is not clear at the present time. We studied the mechanism to analyze the cause of unexplained infertility, the appropriate timing of insemination, and the environment of spermatozoa prior to fertilization. For this study, we examined the effects of Ca++, Mg++, Kallikrein, Phospholipase A2, p-bromophenacyl bromide (Phospholipase A2 specific inhibitor), Lysophosphatidyl choline, Arachidonic acid, and Glyceryl monooleate using in vitro penetration assay employing zona- free hamster eggs. Results obtained were as follows. When human spermatozoa were incubated in mBWW with Ca++ or (and) Mg++ free medium, the acrosome reaction was inhibited. When human spermatozoa were incubated in mBWW with Kallikrein (1.0-4.0 KU ml), the acrosome reaction was promoted. When Phospholipase A2 was used at concentrations of 0.2 and 2.0 unit/ml, penetration rates showed the same tendency as in the control. But when p-bromophenacyl bromide was tested at concentrations of 1 X 10(-5) - 1 X 10(-3)M, penetration rates were inhibited when compared with the control. When human spermatozoa were incubated in medium containing Lysophosphatidyl choline (50 micrograms/ml), Arachidonic acid (5-50 micrograms/ml), and Glyceryl monoleate (300-400 micrograms/ml), the acrosome reaction was accelerated.