title: Comparative study of tamoxifen and raloxifene on endometrial cell proliferation of female rats in persistent estrus.
abstract: OBJECTIVE
  The objective of the study was to compare the effect of tamoxifen and raloxifene on the endometrium of female rats in persistent estrus, by Ki-67 protein expression.
  
  
  METHODS
  The study comprised 60 Wistar-Hannover female rats in persistent estrus, induced by a single subcutaneous dose of 1.25 mg of testosterone propionate on the second day of age. At 90 days of life, the animals were randomly divided into 3 groups of 20 animals each. Group 1 (control), received only placebo; group 2, the animals were treated with tamoxifen, 250 μg/d; and group 3, the rats were treated with 750 μg/d of raloxifene by gavage during 30 days. Then, the animals were killed, and the endometrium was removed for immunohistochemical analysis of Ki-67 antigen expression. Statistical analysis was performed by β regression model (P < 0.05).
  
  
  RESULTS
  Mean percentages of Ki-67 protein expression in the endometrium of rats in persistent estrus were 43.21% ± 3.39%, 7.36% ± 0.95%, and 7.20% ± 0.76% in groups 1, 2 and 3, respectively (P < 0.001). There was no statistical difference between groups 2 and 3 (P = 0.7159).
  
  
  CONCLUSIONS
  The present results indicate that, at the doses and during the time of treatment used, both tamoxifen and raloxifene induce atrophy in a similar way of endometrial epithelium of rats in persistent estrus.
authors: Department of Gynecology, Federal University of Piaui, Teresina, Piaui, Brazil. dorivalmrjr@gmail.com
authors: Dorival Mendes
authors: DM
authors: Rodrigues Junior
authors: Alesse Ribeiro
authors: AR
authors: Dos Santos
authors: Pedro Vitor
authors: PV
authors: Lopes Costa
authors: Benedito Borges
authors: BB
authors: da Silva
mesh_terms: D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects*; D004717:Endometrium / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004971:Estrus; D005260:Female; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism*; D020849:Raloxifene Hydrochloride / Q000494:pharmacology*; D011897:Random Allocation; D051381:Rats; D012044:Regression Analysis; D020845:Selective Estrogen Receptor Modulators / Q000494:pharmacology*; D016037:Single-Blind Method; D013629:Tamoxifen / Q000494:pharmacology*
chemical_list: D019394:Ki-67 Antigen; D020845:Selective Estrogen Receptor Modulators; D013629:Tamoxifen; D020849:Raloxifene Hydrochloride