title: Interruption of early pregnancy in the monkey with mestranol and 5-oxa-17-phenyl-18,19,20-trinor prostaglandin F1 alpha methyl ester.
abstract: Prior work has shown that 5-oxa-17-phenyl-18,19,20- trinor prostaglandin F1 alpha methyl ester (PGF-analog) inhibits luteal progesterone secretion, but does not shorten menstrual cycles in human chorionic gonadotropin (hCG)-treated, nonpregnant monkeys. This report demonstrates that a combination treatment of PGF-analog and mestranol not only reduces blood progesterone concentrations in the hCG-treated monkey, but also results in a significant shortening of menstrual cycles. The corpus luteum-inhibiting activity of PGF-analog in hCG-treated, nonpregnant monkeys was not enhanced by simultaneous administration of nonestrogenic steroids (norethisterone, oxymetholone, azastene , 17 alpha-allyl-3-methoxy-1,3,5(10)- estratrien-17 beta-ol). Most importantly, pregnancy was interrupted in 11 or 12 monkeys when PGF-analog and mestranol were administered on Day 28 of fertile menstrual cycles; this abortifacient activity of the prostaglandin-estrogen treatment was not prevented by concomitant administration of progesterone. Administration of PGF-analog and mestranol in the third trimester terminated pregnancy in only 1 of 3 monkeys. The data indicate that a combination treatment of PGF-analog and mestranol is highly effective for the termination of early pregnancy in the monkey. Although PGF-analog and mestranol clearly inhibit the monkey corpus luteum, it is unlikely that this activity is essential for the abortifacient activity of the prostaglandin-estrogen treatment.
mesh_terms: D000019:Abortifacient Agents; D000818:Animals; D006063:Chorionic Gonadotropin / Q000097:blood*; D003338:Corpus Luteum / Q000187:drug effects; D004347:Drug Interactions; D004958:Estradiol / Q000097:blood; D005260:Female; D008253:Macaca mulatta; D008598:Menstruation / Q000187:drug effects*; D008656:Mestranol / Q000494:pharmacology*; D009640:Norethindrone / Q000494:pharmacology; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D011461:Prostaglandins F, Synthetic / Q000494:pharmacology*
chemical_list: D000019:Abortifacient Agents; D006063:Chorionic Gonadotropin; D011461:Prostaglandins F, Synthetic; D011374:Progesterone; D004958:Estradiol; C041755:5-oxa-17-phenyl-18,19,20-trinor prostaglandin F1 alpha methyl ester; D008656:Mestranol; D009640:Norethindrone