The possible mode of action of phostaglandins. XII. Differential effects of phostaglandin F2alpha in inducing premature evacuation of conceptos in the intact and castrated pregnant rat.
A single injection of 2.0 mg/kg prostaglandin F2alpha(PGF2alpha) on day 18 of pregnancy was consistent in inducing premature labor by 72 h following the injection. Conversely, castration before PGF2alpha on day 18 of pregnancy made the animals almost inert to PGF2alpha and only 20% of the treated animals showed premature evacuation of the conceptus. Injection of 10mug of estradiol cyclopentylpropionate (ECP) on day 18 was, however, found to be effective in emptying the gravid uteri of 100% castrated pregnants by 72 h. Indomethacin, a consistent inhibitor of prostaglandin biosynthesis and release, along with ECP in an identical experimental situation was found to be ineffective in reversing the ECP-induced premature parturition in castrated pregnants. The importance of intact ovary for the action of PGF2alpha concerning premature labor in rats has been discussed.
D000818:Animals; D002369:Castration; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D007751:Labor, Induced; D011247:Pregnancy; D011270:Pregnancy, Animal; D011460:Prostaglandins F / Q000494:pharmacology*; D051381:Rats; D013997:Time Factors; D014590:Uterine Contraction / Q000187:drug effects*
D011460:Prostaglandins F; D004958:Estradiol