Influence of Estrogens on Mouse Uterine Epidermal Growth Factor Precursor Protein and Messenger Ribonucleic Acid

Abstract

Estrogens stimulate the in vivo proliferation of epithelial cells of the mouse uterus. The cumulative evidence from several earlier studies suggests that the mitogenic effect of estrogens is mediated indirectly through a polypeptide growth factor. The primary focus of the present investigation was to determine whether an epidermal growth factor (EGF) -related polypeptide originates in the uterus of the immature or adult mouse under normal or altered estrogen status. Hybridization experiments revealed the presence of the 4.7- kilobase prepro-EGF mRNA in uteri of immature CD-I mice. The level of this mRNA was augmented at least 2-fold in immature mice treated for 4 days with estrogen, but levels remained markedly low compared to those in submaxillary gland or kidney. Two preparations of pooled uterine luminal fluid from estrogen-treated immature mice contained EGF immunoreactivity (1.2 and 1.7 ng/ml) that was stable in response to acid (50 mM acetic acid) and heat. Negligible EGF (Endocrinology122: 2355–2363, 1988)