Müllerian duct maintenance in heterotypic organ culture after in vivo exposure to diethylstilbestrol.

Prenatal exposure to diethylstilbestrol (DES) results in the persistence of Müllerian ducts in male offspring. The influence of DES on Müllerian duct regression was studied using an organ culture system in which DES-treated or control indifferent ducts (embryonic reproductive tracts) were cocultured along with treated or control embryonic testes. Prenatal DES exposure was by sc injection of the mother (100 micrograms/kg BW) on days 9 through 12 of gestation. Embryonic tissues were removed on day 13 of gestation and cultured for 72 h. In organ culture, Müllerian duct regression, comparable to that seen in vivo, occurred when control reproductive tracts were associated with control testes. However, maintenance of the Müllerian duct was observed in 100% of the tissues when DES-treated testes and DES-treated reproductive tracts were cultured together. When recombinations were formed by the association of control reproductive tracts and DES-treated testes, there was regression of the Müllerian duct (87%). However, in the combinations of DES-treated reproductive tracts and control testes, 41% of the cultured tissue demonstrated partial regression of the Müllerian duct, and 59% showed no regression. These data support previous in vivo results that prenatal exposure to DES has an inhibitory effect on Müllerian duct regression and further suggest that this inhibitory effect is mainly due to a decrease in responsiveness of the treated embryonic Müllerian duct.