Stimulation of the zona-free hamster ova penetration efficiency by human spermatozoa after 17β-estradiol treatment

Abstract

17β-Estradiol (E2) stimulated the zona-free hamster ova penetration by human spermatozoa from both fertile and subfertile men after 5 hours of incubation in vitro. For spermatozoa samples from fertile men, the mean penetration rates increased significantly (P<0.05), from 35.6% ± 3.5% (control) to 60.1% ± 5.8% (E2 = 50 ng/ml) and 50.5% ± 2.6% (E2 = 100 ng/ml), respectively. E2 also increased the mean penetration rates of spermatozoa samples frm subfertile men significantly (P<0.05), from 10.2% ± 1.8% (control) to 30.5% ±7.2% (E2 = 50 ng/ml) and 33.1% ± 6.6% (E2 = 100 ng/ml), respectively. These findings indicate that E2 can affect the fertilizing ability of human spermatozoa in vitro.