Protein secretions in mouse uterus after methoxychlor or estradiol exposure

Four-month-old, ovariectomized mice were treated with 14 daily ip injections of either 10.0 micrograms of 17 beta-estradiol or 1.0 mg technical grade methoxychlor. Uterine luminal proteins were radiolabeled with 35S-methionine and run on 2-dimensional electrophoresis gels. The influence of methoxychlor or estradiol was compared to untreated controls by examining reproductive tract weights, uterine histology, and the patterns of uterine protein secretions. The data indicate that the stimulation of the uterus in ovariectomized, adult mice by methoxychlor is indistinguishable from that caused by estradiol. Both substances alter reproductive tract weights, promote cellular hypertrophy, stimulate uterine development, and induce the secretion of comparable levels of incorporation of methionine into a large number of proteins. The data further indicate that the alterations in gene expression promoted by estradiol in terms of secreted proteins appear to be qualitatively similar to those caused by the pesticide methoxychlor.