Pathological changes in female C3H mice continuously fed diets containing diethylstilbestrol or 17beta--estradiol.

To study the long term effects of estrogen administration in mice, virgin female C3H/HeJ mice are being fed diets containing 0, 10, 100 or 500 ppb of diethylstilbestrol (DES) or 0, 100, 1000, or 5000 pph of 17beta-estradiol (E2) from 6 to 110 weeks of age. C3HeB/FeJ mice are being fed diets containing 08 10, 100, or 500 ppb DES FROM 6 TO 136 WEEKS OF AGE. Pathologic studies were conducted on 396 such mice sacrificed at 52 weeks and on over 500 others sacrificed at various intervals. After 52 weeks on 500 ppb DES or 5000 ppb E2, the cervix of both populations often showed stromal mucoid changes and adenosis characterized by focal replacement of squamous by columnar epithelium lining the cervical canal assoicated with glandular downgrowths into the subjacent stroma. The uterine horns showed hyperplastic glands, which often penetrated the muscularis, and focal endometrial and perivascular hyalin deposits. The ovaries showed atrophy with absence of corpora lutea. Ceroid deposits were increased in the ovaries and adrenals. Sternal bony trabeculae were increased. The incidence of uterine cervical adenosis and of mammary hyperplastic alveolar nodules and tumors (mainly type B, Dunn's classification), was higher in C3H/HeJ than in C3HeB/FeJ mice. Mice on lower doses of DES or E2 had less frequent and severe similar changes. Tumors observed to date only in estrogen-treated mice included 4 endometrial adenocarcinomas and an adenoacanthoma of a uterine horn, 14 cervical adenocarcinomas often appearing to arise from areas of adenosis, a vaginal squamous cell carcinoma, a cervical granular cell myoblastoma, 1 sternal and 3 cranial osteosarcomas, and a mesothelioma. The majority of the malignancies occurred in C3H/HeJ mice. These findings indicate that the mammary tumor virus factor facilitates DES-induced mammary tumorigenesis in C3H mice and may contribute to other DES-induced malignant and premalignant lesions.