The protein-mapping technique of O'Farrell is being used to study the synthesis of total protein in embryonic and postnatal mouse genital tracts. Normal differentiation in Mullerian and Wolffian ducts from mouse fetuses beginning with day 14 through birth is being followed by 35S-methionine incorporation into protein. High resolution maps of immature and mature mouse uteri are also being developed to establish end points of differentiation. There are approximately 400 protein spots detectable in each pattern developed thus far. Some 5% of the detectable proteins are either sex or developmental stage specific. The effects of prenatal and postnatal dithylstilbestrol on fetal and immature uteri protein synthetic patterns will be assessed.