Figure 4.

Diagram using CSF2 as an example of how changes in embryokine secretion by the endometrium could affect postnatal phenotype. When the embryo enters the uterus at day 4 or 5 of development it is exposed to CSF2 secreted by the endometrium. CSF2 acts in a sex-dependent manner to affect competence of the embryo to develop to the blastocyst stage and to initiate the process of trophoblast elongation necessary for pregnancy maintenance. CSF2 also acts at the morula or blastocyst stage to modify the developmental program of the embryo. Exposure to CSF2 during the morula to blastocyst period changes gene expression in the female fetus and placenta at day 86 of gestation, caused at least in part by changes in DNA methylation. (as observed at day 15 of gestation), and leads to changes in postnatal function characterized by increased body weight in the juvenile period.