[Estrogenic and contraceptive activity of 17-R-hydroximino derivatives of 9alpha-hydroxy-11beta-nitroxyestrones].

: The estrogenic or uterotropic (UA) and contraceptive (CA) activity of two modified steroids representing 17-R-oximino-9 alpha-oxy-11 beta-nitroxyestrone derivatives (compounds I and II) was experimentally studied by oral administration in female rats in comparison to ethynylestradiol (EED) and mestranol. Compounds I and II showed significant UA (about half that of EED and mestranol) and a pronounced contraceptive effect (exceeding that of mestranol). The dissociation of the drug effects for CA is also indicated by the index of contraception (IC) or the CA/UA ratio. The administration of compounds I and II did not lead to a loss of animals in the acute toxicity tests on female mice.