Induction of uterine protein synthesis by synthetic progestins.

The capacity of artificial progestins, each possessing a C-19 methyl group, to stimulate protein synthesis in the uteri of castrated New Zealand White rabbits was studied in an attempt to screen for this type of progestational activity. It is apparent that modifications of the 4-pregnen-3,20-dione molecule not only alter total protein production, but also effect changes in the synthesis of the uterine protein, blastokinin, in comparison with the effect of unaltered progesterone. This indicates that altering the molecular configuration of progesterone offers contraceptive potential through its ability to influence the preimplantation uterine environment.