EFFECTS OF PROSTAGLANDIN-E2 AND F2-ALPHA ON PERIIMPLANTATION DEVELOPMENT OF MOUSE EMBRYOS INVITRO

The effects of exogenous prostaglandin (PG) E2 and F2-alpha on the morphology and lactate dehydrogenase (LDH) activities of pre-implantation mouse embryos in vitro were studied. A 24-hour exposure from 0.01 to 10-mu-g/ml of PGE2 at the 4-cell or morula stages had no effect on the morphology of embryos during the 144 hours in culture. Exposure to 10-mu-g/ml PGE2 at the blastocyst stage accelerated and enhanced spreading of the trophoblast in vitro. Embryos treated at 0.01 to 10-mu-g/ml PGE2 at various stages all showed a more rapid decline in LDH activity from morula to blastocysts. Treatment with 50 or 100-mu-g/ml PGE2 led to abnormal morphology of embryos in vitro. In contrast, continuous treatment with 0.01 to 100-mu-g/ml PGF2-alpha from 4-cell to early post-implantation (day 8) had no effect on the morphology of embryos, although breakdown of LDH was again accelerated. These results suggest that the peak of PGE2 secretion on day 4 of pregnancy in mice may enhance trophoblastic outgrowth, and the lower levels of PGE2 and PGF2-alpha secreted earlier in pregnancy modulate the development of pre-implantation mouse embryos.