Abstract
To investigate whether early pregnancy factor (EPF) is necessary for embryonic development and implantation, anti-bovine EPF antibody was injected (2.5 mg/rat per injection) into pregnant rats intraperitoneally at 12, 36, 60 and 84 h after mating (total dose of the antibody; 10 mg). By 4.2 days post coitum (p.c.), 47.3% of embryos in the group of animals treated with anti-EPF antibody had developed to the blastocyst stage, compared with 97.2% and 95.4% in the control groups (injected with anti-nonpregnancy antibody and saline, respectively). Rats were administered with 2.5 mg of anti-EPF antibody on 0.5 and 1.5 day p.c.(postfertilization period: group 1), on 3.5 and 4.5 day p.c. (preimplantation period: group 2), and on 6.5 and 7.5 day p.c. (postimplantation period: group 3). When the animals were examined on 10 day p.c., the implantation rates in group 1 and group 2 had significantly decreased by 49.5% and 47.5%, respectively, compared with the control groups which were given injections of either anti-nonpregnancy antibody or saline. In group 3, however, the implantation rates had not been affected. Our data essentially agreed with the results of Igarashi [1] and Athanasas-Platsis et al. [2, 3] who investigated effects of anti-mouse or human EPF antibody in pregnant mice, and showed that anti-bovine EPF antibody crossreacted with rat EPF in vivo.
