Origin and Function
Early embryos are not believed to directly produce EPF. Rather, embryos are believed to produce some other chemical that induces the maternal system to create EPF. After implantation, EPF may be produced by the conceptus directly.
EPF is an immunosuppressant. Along with other substances associated with early embryos, EPF believed to play a role in preventing the immune system of the pregnant female from attacking the embryo. Injecting anti-EPF antibodies into mice after mating significantly reduced the number of successful pregnancies and number of pups; no effect on growth was seen when mice embryos were cultured in media containing anti-EPF antibodies. While some actions of EPF are the same in all mammals (namely rosette inhibition), other immunosuppressant mechanism vary between species.
In mice, EPF levels are high in early pregnancy, but on day 15 decline to levels found in non-pregnant mice. In humans, EPF levels are high for about the first twenty weeks, then decline, becoming undetectable within eight weeks of delivery.
Recent research has suggested that EPF may be associated with cell proliferation in a wide variety of biological situations, not just embryo development.
Read more about this topic: Early Pregnancy Factor
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