Experimental study of the effect of diethylstilbestrol on the development of the human female reproductive tract.

Female genital tracts from human embryos and fetuses 5-17 weeks post fertilization were grown for 1-3 months in vivo as grafts to athymic female nude mice. The nude mice were either untreated or treated with diethylstilbestrol (DES). In control (untreated) hosts, anticipated normal development occurred with a high degree of precision. Müllerian ducts fused and proliferated, forming a solid uterovaginal canal that later canalized and formed a normal vaginal mucosa. Uterine glands appeared, and the uterine tube developed its highly plicated mucosa. Under the influence of DES, many of these normal developmental processes were adversely affected. Müllerian epithelium was largely obliterated in the fallopian tube and uterine corpus, mesenchymal stratification into endometrial stroma and myometrium was suppressed, plical development in the fallopian tube was inhibited, cervicovaginal epithelial development was abnormal, and vaginal adenosis was observed in several specimens. This in vivo model of human development is discussed in terms of its potential for resolving the mechanisms of normal human genital development and understanding the teratogenic action of DES on the developing human genital tract.