Alterations in the developmental properties of stroma during the development of the urogenital ridge into ductus deferens and uterus in embryonic and neonatal mice.

The ability of mesenchyme from the urogenital ridge to participate in the development of male and female urogenital organs was studied by preparing homo- and heterotypic recombinants of epithelium and stroma from ductus deferens and uterus of neonatal mice. The recombinants as well as intact 14-day old embryonic urogenital ridges (URG) were grown for two to eight weeks in adult male and female hosts. The development of ductus deferens and seminal vesicle from female UGR's grafted into male hosts and uterus from male UGR's grafted into female hosts demonstrate that the mesenchyme of embryonic UGR's is capable of participating in the development of either male or female urogenital structures. During normal development of the female urogenital tract, the bisexual morphogenetic potentiality of UGR mesenchyme persists postnatally as demonstrated by the ability of uterine stroma to support normal differentiation of epithelium of ductus deferens in male hosts. Conversely, during the normal development of the male urogenital tract, the morphogenetic potentiality of mesenchyme of the urogenital ridge is restricted as stroma from the ductus deferens appears incapable of participating in uterine morphogenesis in male or female hosts. These differences in the developmental properties of UGR stroma may be attributed to differences in hormonal conditions in male and female fetuses.