Estrogen Regulation of Epidermal Growth Factor Receptor Messenger Ribonucleic Acid

Previous studies have demonstrated that 17 beta-estradiol (E2) causes a 3-fold increase in epidermal growth factor (EGF) receptors in uterine membranes. We now report that the increase in uterine EGF receptor levels is due to an increase in the steady-state levels of EGF receptor mRNA. After a single E2 injection, EGF receptor mRNA levels, as determined by RNA blots, increase 3- to 4-fold between 1 and 3 h, remain elevated at 6 h, and decline between 12 and 18 h. The effect is specific for E2 since the nonestrogenic hormones progesterone, dexamethasone, 5 alpha-dihydrotestosterone, and the inactive stereoisomer of E2, 17 alpha-estradiol, are without effect. E2-Mediated increases in EGF receptor mRNA levels are blocked by actinomycin D but not by puromycin. Taken together, these results indicate that E2 regulates the level of EGF receptor by increasing the steady-state concentration of EGF receptor mRNA in vivo.