Effects of sex hormones on oncogene expression in the vagina and on development of sexual dimorphism of the pelvis and anococcygeus muscle in the mouse.

Neonatal treatment of female mice with diethystilbestrol (DES) is known to induce ovary-independent persistent proliferation and cornification of vaginal epithelium. This irreversibly changed vaginal epithelium persistently expressed higher levels of c-jun and c-fos mRNAs, which was not altered by postpubertal estrogen. Sexual dimorphism was encountered in mouse pelvis and anococcygeus muscle. Postpubertal estrogen changed the shape of the pelvis to the female type and postpubertal androgen changed it to the male type. Neonatal exposure to DES and to the antiestrogen tamoxifen altered the developmental pattern of the pelvis, which contained lower concentrations of calcium and phosphorus than controls. The size of anococcygeus muscle was increased by postpubertal androgen but decreased by postpubertal estrogen. However, neonatal estrogen (DES) exposure permanently enlarged the anococcygeus muscle. Thus, neonatal treatment of mice with estrogen and antiestrogen results in irreversible changes in nonreproductive as well as reproductive structures.