Endocrine profile of a new long-acting progestational steroid: Org 2793. (Abstract only)

The endocrine profile of a new long-acting progestational steroid is presented. Org 2793 (16alpha-ethyl-21-heptanoyloxy-19-nor-4-pregnene-3 20-dione showed strong progestational activity without unwanted side effects after a single sc administration of an oily solution as determined in the following tests. Org 2793 was active in the Clauberg-Junkmann assay and maintained pregnancy in ovariectomized rats hamsters guinea pigs and rabbits. Parturition was delayed in intact pregnant rats. It induced deciduoma formation in ovariectomized mice and was active in the McGinty test. The duration of activity is dose-dependent as shown by suppression of estrus in mature rats. Org 2793 showed antiestrogenic activity in spayed rats treated with estradiol. In estrous rabbits sperm migration through the cervix was inhibited by Org 2793: unfertilized ova were present in the tubes after human chorionic gonadotropin induced ovulation and vaginal insemination. A high dose of Org 2793 did neither display androgenic nor antiandrogenic activities. Masculinization or feminiation (assessed on the basis of ano-genital distances) was not observed in offspring of rats resulting from pregnancies maintained by Org 2793. Fertility of the FL generation reared by foster mothers of New Zealand white rabbits treated with high doses of Org 2793 during pregnancy was normal. No teratogenic effects were observed in part of the offspring examined after Caesarian section. Dependent on the test used high doses of Org 2793 induced no or slight corticosteroidlike effects in rats. (Full text)