Induction of uterine protein synthesis by synthetic progestins

Abstract

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.

PIP: The production of blastokinin relative to total uterine proteins in response to various synthetic progestins possessing a C-19 methyl group was studied in the uteri of castrated rabbits. Treatment with any of the 10 synthetic progestins resulted in higher levels of total uterine protein than treatment with progesterone. Only 4 of the progestins screened produced a lower proportion of total protein that was blastokinin than produced by progesterone. Even 17betaestradiol stimulated protein production to a degree nearly equal to that of progesterone. The results show that modifications of the 4-pregnen-3,20-dione molecule affect total protein production in the uterus and alter the synthesis of blastokinin in comparison with the effect of progesterone. The implications of the alteration of the molecular configuartion of progesterone for contraceptive purposes are discussed.