Autoradiographic study of the effects of estrogen on in vivo incorporation of 3H-uridine into uterine smooth muscle and stromal RNA in the aging ovariectomized mouse.

An autoradiographic study was made of de novo RNA synthesis and nuclear area in endometrial stroma and myometrium in ovariectomized C57B1/6J mice. A comparison of uterine tissue from young adult (4 to 7 month old) mice was made with tissue from animals of the age of decreased fertility (15 months of age). In mice receiving exogenous estradiol-17 beta there was an age related decrease in nuclear grain counts 60 min after injection of 3H-uridine which was more pronounced in endometrial stroma than in myometria when mice were compared with oil injected controls of the same age. The mean nuclear area of both cell types was greater in estrogenized mice than in control mice. The decrease in endometrial stromal response to exogenous estrogen is consistent with, and may contribute to, decreasing fertility with advancing maternal age.