Failure of hamster eggs fertilized in vitro to extrude the second polar body correlates with high levels of polyspermy.
The occurrence of second polar body (PB2) retention in in-vitro fertilized hamster eggs is reported. Of 2,872 eggs examined, 6.9% (199 eggs) failed to extrude PB2. Eggs that failed to extrude PB2 were more likely to be polyspermic than eggs with PB2 (63% and 14.6%, respectively), and the number of fusing sperm per egg was higher in the abnormal eggs. These data indicate that eggs which fail to extrude PB2 have an impaired block to polyspermy. The level of PB2 retention varied between females and ranged from all eggs extruding PB2 to 20% of the eggs failing to extrude PB2 (41% and 4% of the females, respectively). There was no correlation within a female between the percentage of eggs that failed to extrude PB2 and the level of polyspermy in the sister eggs with PB2. Therefore, regardless of the condition of their sister eggs, eggs that fail to extrude PB2 have an impaired block to polyspermy and eggs that extrude PB2 have a normal block.
D000818:Animals; D006224:Cricetinae; D005260:Female; D005307:Fertilization in Vitro; D008297:Male; D008540:Meiosis; D009865:Oocytes / Q000166:cytology* / Q000648:ultrastructure; D013084:Sperm-Ovum Interactions