Effects of simultaneous treatment with estrogen and testosterone on the uterus of female adult rats.
BACKGROUND
Testosterone (T) associated with estrogen (E) has been used in hormonal replacement therapy in postmenopause women and the effects of this hormonal association on the uterus are not known.


OBJECTIVE
To study the effect of long-term simultaneous exposure to testosterone and estrogen on the uterus of non-castrated adult female rats.


METHODS
Groups of ten adult noncastrated female Wistar rats were treated with non-esterified testosterone and beta estradiol (subcutaneous implants with 50 mg of each hormone) or with testosterone cipionate and estradiol valerate (weekly intramuscularly or by subcutaneous injection of respectively, 2.85 mg/kg and 0.166 mg/kg). Control groups received no treatment (10 rats) or injections of diluents (6 rats). All animals were killed six months after hormonal exposure.


RESULTS
All rats treated with T+E developed hyperplasia and hyperkeratosis of the vaginal and cervical epithelium and focal metaplasia with keratinization of the endocervical and endometrial epithelium. Ascending pelvic inflammatory disease with pyometra and tuboovarian abscesses were frequent (25% mortality until the end of the experiment).


CONCLUSIONS
Testosterone associated with estrogen induced metaplasia of the genital epithelium but did not induce neoplastic lesions. The metaplasic lesions reduced the mucosal defense mechanisms enhancing ascending genital inflammatory disease. Although metaplasia of the cervical and endometrial epithelium has been observed after estrogen exposure in rats, testosterone does not appear to inhibit these estrogen effects.
Ramos
A M G
AM
Department of Gynecology and Obstetrics, Health Sciences School of the Santa Casa of Vitória, ES, Brazil.
Camargos
A F
AF
Pereira
F E L
FE
D000818:Animals; D002584:Cervix Uteri / Q000187:drug effects; D004343:Drug Implants; D004347:Drug Interactions; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D005260:Female; D006965:Hyperplasia / Q000139:chemically induced*; D007267:Injections; D008679:Metaplasia / Q000139:chemically induced*; D051381:Rats; D017208:Rats, Wistar; D013739:Testosterone / Q000494:pharmacology*; D014599:Uterus / Q000187:drug effects*
D004343:Drug Implants; D013739:Testosterone; D004958:Estradiol