Mechanism of action of an orally active PGE 1-analogue in pregnant guinea-pigs

Abstract

At the 43rd day of pregnancy 6 Experimental guinea-pigs were treated orally with the PGE 1-analogue, CP 48,630 (Pfizer), while 6 animals served as vehicle Controls. An average dose of 1.5 mg CP 48,630 compromized the conceptus and provoked abortion in 6.6±1.4 hours in all 6 Experimental guinea-pigs. The vehicle Controls, with all pregnancies continuing intact, had high P-levels in peripheral and uterine vein plasma, ovaries, placenta and uterine tissue and low PGF-levels in the uterine vein plasma. In contrast, in the Experimental animals the P-levels were significantly reduced and the PGF-levels elevated. Thus, the “PG-Impact” rapidly tipped the regulatory balance of pregnancy, compromized the conceptus (all fetuses were dead and the placentae discolored). and provoked the evolution of uterine activity culminating in abortion.