ESTROGEN EFFECTS ON CHROMOSOME-NUMBER AND SISTER CHROMATID EXCHANGES IN UTERINE EPITHELIAL-CELLS AND KIDNEY-CELLS FROM NEONATAL MICE

Female mice of the NMRI strain were treated with a high dose (5-mu-g) or a low dose (10(-2) mu-g) of the synthetic estrogen diethylstilbestrol (DES) or estradiol-17-beta (E2) 48 and 24 hr, 24 hr, or 12 hr before death on day 3 after birth. Cultures of epithelium from the uterine cervix and uterine horns as well as of kidney cells were set up, and, after a culture period of 3 days, cells were studied for chromosome number and sister chromatid exchanges. Cervical cells from control females had a distinct peak of tetraploid cells, which was depressed after DES treatment but less so after E2 treatment. The tetraploid peak was lower in uterine horn epithelium and was less influenced by DES. No indications were obtained for an estrogen-induced aneuploid cell population in the uterine horn epithelium or cervical epithelium. The incidence of cells with a high number of sister chromatid exchanges (HFCECs) was only about one-fifth in uterine horn epithelium from control females compared with cervical epithelium from the same females. In the cervical epithelium, DES at both dose levels and E2 at the high dose induced an increased and similar incidence of HFCECs (from about 12.5% in controls to about 35%), which was not related to estrogen exposure time. In uterine horn epithelium, the incidence of HFCECs increased from 2.5% in controls to 8.5% after DES treatment. It is postulated that there is a more pronounced genomic plasticity in the cervical epithelium compared with the uterine horn epithelium. The estrogens had no effect on chromosome number of HFCECs in kidney cells.