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

Abstract

The objective of the present investigation was to purify early pregnancy factor (EPF)-like substance(s) from a pregnant bovine ovarian extract and in vitro fertilized ovum culture medium (IVF-OCM). Both the ovarian extract and IVF-OCM had EPF-like activity. These EPF-like substance(s) bound with CM-Sepharose and CNBr-activated Sepharose coupled with anti-EPF IgG but did not bind with a HPLC-DEAE column. The EPF-like substance(s) purified from the ovary and IVF-OCM had EPF-like activity (RIT≥5) at M.W. 17-38 KD and M.W. 21-30 KD, respectively. SDS-PAGE analysis revealed that the ovarian extract and IVF-OCM positive fractions had a band of 21.5 KD similar to that of EPF purified from pregnant bovine serum. Antiserum to HPLC fraction III (IVF-OCM origin, RIT≥5) decreased the RIT value of pregnant bovine serum from 6 to 3 and reacted with a band of 21.5 KD protein purified from bovine pregnant serum. Therefore, these two EPF-like substance(s) and EPF from pregnant serum may be similar substances.