Pregnancy-terminating effect of human chorionic gonadotrophin in rats.
A single intramuscular dose of HGC(50) i.u. or more per rat) was able to induce fetal resorption and eventual termination of pregnancy when injected on Day 4 or between days 7 and 11 of pregnancy. This dose was inactive when administered on Day 12 of pregnancy. A single large dose (500 i.u./rat) induced fetal resorption when administered even on Day 12 of pregnancy. In intact rats treated with HCG, daily doses of progesterone were unable to maintain normal implantation; in ovariectomized rats treated with HCG, daily preges. Terone did succeed in maintaining pregnancy in many of the animals. It is suggested that fetal resorption and the eventual pregnancy-terminating effects of HCG in rats are mediated through the alteration of normal ovarian steroidogenesis.
D000818:Animals; D002369:Castration; D006063:Chorionic Gonadotropin / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005313:Fetal Death / Q000139:chemically induced*; D005865:Gestational Age; D006801:Humans; D007273:Injections, Intramuscular; D010053:Ovary / Q000187:drug effects; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000187:drug effects*; D011374:Progesterone / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D013256:Steroids / Q000096:biosynthesis; D013997:Time Factors
D006063:Chorionic Gonadotropin; D013256:Steroids; D011374:Progesterone