Relative potentiality of some contragestational agents on trauma induced deciduoma formation in immature rats.

Relative progestational and antiprogestational profile of four contragestational agents, viz. RMI-12,936, RU-38,486, STS-557 and WIN-32,729, known to possess either or both the properties in other test systems, was determined in immature rats using deciduoma induction as marker. The deciduoma was produced by needle traumatization in one of the uterine horn, and the extent of stimulation was analysed, both macro and microscopically, against the control nontraumatized horn. The results indicated that the agents which demonstrated better potentiality(ies) as progestational and/or antiprogestational in this bioassay exhibit contraceptive efficacy at relatively lower doses as compared to those that showed mild to moderate potentiality.

Effect of RMI 12,936, an antiprogestational steroid on decidual cell reaction and embryos in rat.

Subcutaneous administration of RMI 12,936 at a dose level of 2 mg/rat on day 5 of unilaterally pregnant rat having trauma-induced decidual cell reaction (DCR) in the contralateral uterine horn, suppresses DCR, induces resorption of implanted embryos and leads to decrease in the plasma level of progesterone. Progesterone replacement (D 5-8) in this situation reverses DCR suppressive effect of RMI 12,936 but fails to prevent resorption of implanted embryos. It is concluded that possibly the drug simultaneously exerts embryotoxic as well as luteolytic effects, but these effects are independent.