Early pregnancy factor: large scale isolation of rosette inhibition test-active polypeptides from ovine placental extracts

The 'early pregnancy factor' revisited: the effect of ammonium sulfate on the capacity of pregnant mouse sera to express activity in the rosette inhibition assay

“…Studies on the nature of some of the molecules and mechanisms involved in the rosette inhibition assay (Orozco et al, 1986(Orozco et al, , 1990Clarke et al, 1990a, b) that allow the expression of increased rosette inhibition titres and also on some of the molecules and mechanisms by which pregnancy sera achieve this effect (Clarke et al, 1987Di Trapani et al, 1991) have provided some new insights. Characterization of human (Di Trapani et al, 1991) and ovine .…”

Detection of Early Pregnancy Factor in the Sera of Cows Whose Uteri were Infused with Trophoblastic Cell Culture Medium.

“…The fetal placenta originates in the trophoblast at an initial stage of its development. Polypeptides that inhibit rosette formation have been detected in ovine placental extract and EPF-like activity has been observed in the culture medium of chorionic villi [10,11]. EPF activity in human trophoblastic cell culture medium has been positive with a maximum level occurring during the first 8 days when trophoblastic cells at gestational weeks 7 to 9 were isolated and cultured [17].…”

“…EPF has also been detected in sera of pregnant cattle [6] and mares [7] and in the culture medium of human in vitro fertilized ova [8]. Also an EPF like substance has been detected in the culture medium of bovine fertilized ova [9], in human chorionic villi [10] and in ovine placental extract [11]. It is considered that EPF is an indicative signal for successful fertilization and embryonic well-being [3,12,13].…”

Early Pregnancy Factor: EPF-Like Substance(s) Purified from Pregnant Bovine Ovary and in vitro Fertilized Ovum Culture Medium

“…The ovarian extract was prepared according to the method of Clarke et al [12]. Ovarian tissue (1.2 g) was separated from an ovulated left ovary and homogenized with 0.1 M ammonium bicarbonate (pH 9.5) at 3000 r.p.m.…”