Response of the vagina of the spayed guinea pig to low or high doses of estrogen.

Abstract

AbstractSpayed ginea pigs injected daily for 6 to 10 days with 10, 50, 150 μg of estradiol cyclopentylpropionate (ECP) developed a mucified vaginal epithelium, similar to that observed during pregnancy or following treatment of ovariectomized animals with 5 mg progesterone and 1 μg of ECP.The epithelium did not mucify in spayed guinea pigs given 0.01 to 1.0 μg ECP daily for 10 or more days. Vaginal cornification developed only in animals treated with 1 μg ECP but the reaction was transitory and the keratinized cells were soon replaced by a stratified squamous epithelium.Spayed and adrenalectomized guinea pigs injected daily with 150 μg ECP developed a stratified squamous epithelium rather than a mucified type. However, the vaginal epithelium was mucified in ovariectomized‐adrenalectomized guinea pigs receiving 150 μg ECP and corticoids or progesterone. This suggests that after treatment with large doses of estrogen the adrenal of the spayed guinea pig produces progestin‐like hormones. These progestins interacting with exogenous estrogen are responsible for vaginal mucification.On the other hand, spayed rats maintained on 1 or 150 μg of ECP showed continuous vaginal cornification, which indicates that there are species differences in the ability of large doses of estrogen to influence the adrenal.