Abortive Expansion of the Cumulus and Impaired Fertility in Mice Lacking the Prostaglandin E Receptor Subtype EP2
Abstract
Female mice lacking the gene encoding the prostaglandin (PG) E2 receptor subtype EP2 (EP2-/-) become pregnant and deliver their pups at term, but with a much reduced litter size. A decrease in ovulation number and a much reduced fertilization rate were observed in EP2-/- females without difference of the uterus to support implantation of wild-type embryos. Treatment with gonadotropins induced EP2 mRNA expression in the cumulus cells of ovarian follicles of wild-type mice. The immature cumuli oophori from wild-type mice expanded in vitro in response to both follicle-stimulating hormone and PGE2, but the response to PGE2 was absent in those from EP2-/- mice. Cumulus expansion proceeded normally in preovulatory follicles but became abortive in a number of ovulated complexes in EP2-/- mice, indicating that EP2 is involved in cumulus expansion in the oviduct in vivo. No difference in the fertilization rate between wild-type and EP2-/- mice was found in in vitro studies using cumulus-free oocytes. These results indicate that PGE2 cooperates with gonadotropin to complete cumulus expansion for successful fertilization.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- August 1999
- DOI:
- 10.1073/pnas.96.18.10501
- Bibcode:
- 1999PNAS...9610501H