Effects of tamoxifen and raloxifene on body and uterine weights of rats in persistent estrus.

PURPOSE: To evaluate the change in body and uterine weights of rats in persistent estrus, a model developed to mimic polycystic ovary syndrome treated with selective estrogen receptor modulators (SERMs) tamoxifen and raloxifene. METHODS: Sixty Wistar-Hannover rats induced by a single subcutaneous dose of 1.25 mg testosterone propionate were divided into three groups of 20 animals: Group I (placebo); Group II (tamoxifen, 250 microg/day) and Group III (raloxifene, 750 microg/day). At 90 days of life, the treatment began for 30 consecutive days, in which the animals were weighed weekly. On the 31st day, the animals were sacrificed and the uterus removed. Data were analyzed statistically by analysis of variance and by the Tukey-Kramer multiple comparisons test (p<0.05). RESULTS: Means of body and uterine weights (g) after treatment were: 227.3+/-2.20 and 0.40+/-0.01; 185.3+/-2.45 and 0.25+/-0.01; 186.4+/-2.20 and 0.27+/-0.01 in Groups I, II and III, respectively (p<0.001). There was no statistical difference between groups II and III for body and uterine weight (p=0.727 and p=0.646, respectively). CONCLUSION: The present results indicate that, at the doses and during the time of treatment used, both tamoxifen and raloxifene reduce in a similar way the body and uterine weights of rats in persistent estrus showing a possible antiestrogenic effect of SERMs under high levels of estrogens.