[The effect of indomethacin on the implantation and metabolism of blastocysts].

The experiments were performed in order to reveal the role of prostaglandins in the implantation process, using indomethacin, a inhibitor of prostaglandin synthesis. Indomethacin was administered to mice on various days of pregnancy, and then the number of implantation sites and the uterine weight per the number of implantation sites were determined on day 10 of pregnancy. Furthermore [3H]uridine incorporation of blastocysts incubated in the medium containing indomethacin with/without prostaglandin F2 alpha was evaluated in vitro. The results were as follows. Indomethacin reduced the number of implantation sites in the uterus and the uterine weight per the number of implantation sites (embryonal growth). Indomethacin inhibited the [3H]uridine incorporation of blastocysts, but prostaglandin F2 alpha counteracted the effect of indomethacin. These results suggested that prostaglandins play a role in inducing implantation and embryonal growth, and that blastocysts might synthesize prostaglandins.