Estrogen regulation of epidermal growth factor receptor messenger ribonucleic acid

Previous studies have demonstrated that 17 β-estra-diol (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 α-dihydrotestosterone, and the inactive stereoisomer of E₂, 17α-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.