title: Comparative effectiveness of three antiprogestins alone and in combination with anordiol in terminating pregnancy in the rat.
abstract: The effectiveness of mifepristone, onapristone, and ORG 31806 alone or in combination with anordiol to terminate pregnancy in the rat was evaluated. ORG 31806 at a dose of 2 mg/kg/day, mifepristone at 4 mg/kg/day, and onapristone at 8 mg/kg/day, terminated pregnancy in all treated animals. Anordiol, an antiestrogen, at a dose of 5 mg/kg/day, terminated pregnancy in all treated animals. Anordiol acted synergistically with all three antiprogestins terminating pregnancy in the rat. The antiprogestins at doses that were either partially effective or non-effective became 100% effective when administered with a non-effective dose of anordiol. Thus, combination of ORG 31806 (1 mg/kg/day) plus anordiol (0.31 mg/kg/ day), mifepristone (1 mg/kg/day) plus anordiol (0.62 mg/ kg/day), and onapristone (2 mg/kg/day) plus anordiol (2.5 mg/kg/day) terminated pregnancy in all treated animals. These combinations of the antiprogestins and anordiol decreased significantly the serum progesterone levels but not serum 17 beta-estradiol levels. The present results indicate that the most potent combination was ORG 31806 plus anordiol.
authors.affiliation: Center for Biomedical Research, Population Council, New York, NY 10021, USA.
authors.forename: B
authors.initials: B
authors.lastname: Dao
authors.forename: G
authors.initials: G
authors.lastname: Vanage
authors.forename: X J
authors.initials: XJ
authors.lastname: Li
authors.forename: C W
authors.initials: CW
authors.lastname: Bardin
authors.forename: S S
authors.initials: SS
authors.lastname: Koide
mesh_terms: D000028:Abortion, Induced / Q000379:methods*; D000284:Administration, Oral; D000818:Animals; D015331:Cohort Studies; D003281:Contraceptives, Postcoital / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004357:Drug Synergism; D004958:Estradiol / Q000097:blood / Q000378:metabolism; D004963:Estrenes / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D005663:Furans / Q000008:administration & dosage / Q000494:pharmacology*; D006067:Gonanes / Q000008:administration & dosage / Q000494:pharmacology*; D006727:Hormone Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D015735:Mifepristone / Q000008:administration & dosage / Q000494:pharmacology*; D009635:Norandrostanes / Q000008:administration & dosage / Q000494:pharmacology*; D011247:Pregnancy; D011374:Progesterone / Q000097:blood / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D003281:Contraceptives, Postcoital; D004338:Drug Combinations; D004963:Estrenes; D005663:Furans; D006067:Gonanes; D006727:Hormone Antagonists; D009635:Norandrostanes; C076197:Org 31806; D015735:Mifepristone; D011374:Progesterone; D004958:Estradiol; C023615:anordiol; C053238:onapristone