Abstract
Progesterone plays an important role in sperm capacitation and acrosome reaction. In this experiment we examined the effect of a progesterone antagonist, RU486, on the penetration of zona-free hamster eggs by human sperm. Media containing 10, 15, 20, 25 or 30 μM RU486 were prepared. In the control medium without RU486, the sperm penetration rate was 80.7%. In the medium with 10 μM RU486, the sperm penetration rate was 67.0%. The rate further decreased as the level of RU486 increased. In the medium with 30 μM RU486, the sperm penetration rate was reduced to 4.8%. This study demonstrates that RU486 inhibits penetration of zona-free hamster eggs by human sperm in a dose-dependent manner.
