[Control of implantation in rats and sows by peroral administration of prostaglandin synthetase inhibitors. 1. Theoretical aspects of control of implantation in swine].

The reproduction situation of swine is considerably affected by embryonic foetal death. Reduction of loss of that origin, therefore, would open up palpable reserves. There is general agreement to the effect that the period close to implantation and the entire first month of gravidity make for the most critical phase of intra-uterine development. Proper mutual adaptation of progesterone and oestrogen levels are among the important prerequisites for favourable implantation conditions. However, fertility of swine was not always enhanceable by administration of progesterone and oestrogen. Tests of laboratory animals have shown that there are additional hormones and control mechanisms, on top of progesterone and oestrogen, which are involved in regulation of the implantation process. For example, higher prostaglandin F2 alpha concentrations in the blood and endometrial tissue of mammals in early gravidity seem to have adverse effects on implantation. The possibility is considered in this paper to eliminate such interference effect of prostaglandin by application of prostaglandin synthetase inhibitors.