Estrogenic activity of DDT: Estrogen‐receptor profiles and the responses of individual uterine cell types followingo,p'‐DDT administration

The administration of o,p'-dichlorodiphenyltrichloroethane (o,p'-DDT) to immature rats stimulates DNA synthesis and cell division in the uterine luminal epithelium (LE), stroma (S), and myometrium (M). The time course of DNA synthesis/cell division in the S and M is similar following administration of o,p'-DDT or 17 beta-estradiol, but the maximum response following pesticide treatment is only 70% of that produced by the hormone. In the LE both compounds yield the same maximum response, but the time course of DNA synthesis/cell division is delayed following o,p'-DDT administration relative to 17 beta-estradiol treatment. The patterns of estrogen receptor retention in uterine nuclei following o,p'-DDT administration are prolonged relative to those observed after 17 beta-estradiol treatment. o,p'-DDT thus produces the uterine hyperplasia characteristic of estrogens, but the magnitude and timing of the response is dependent on the specific cell type observed and is different from that produced by estradiol.