title: [Effects of levonorgestrel subdermal implants on estradiol and progesterone receptors of endometrium and ovarian tissues in rats].
abstract: OBJECTIVE
  To study the influence of subdermal implantation of levonorgestrel (LNG) on the levels of estradiol receptor (ER) and progesterone receptor (PR) in ovaries and endometrium of rats.
  
  
  METHODS
  45 female mature rats were divided into 3 groups: control group, silicon tube group and LNG implants group. Using single-point determination at saturating concentration method, ER and PR levels of both ovaries and endometrium were measured at 15, 30 and 45 days after subdermal implantation of LNG or silicon tube, and compared with that of the control group.
  
  
  RESULTS
  ER and PR levels in LNG group were significantly lower than those in the other 2 groups (P < 0.01). The concentration of ER and PR decreased gradually as implantation prolonged.
  
  
  CONCLUSIONS
  subdermal implantation of LNG resulted in the reduction of ER and PR levels in ovaries and endometrium of rats, which may be related to the mechanism of contraception and breakthrough bleeding after implantation.
authors.affiliation: General Military Hospital of Guanzhou Command Area.
authors.forename: A
authors.initials: A
authors.lastname: Sun
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: J
authors.initials: J
authors.lastname: Kuang
mesh_terms: D000818:Animals; D003280:Contraceptives, Oral, Synthetic / Q000494:pharmacology*; D004717:Endometrium / Q000187:drug effects / Q000378:metabolism; D005260:Female; D016912:Levonorgestrel / Q000494:pharmacology*; D010053:Ovary / Q000187:drug effects / Q000378:metabolism; D019736:Prostheses and Implants; D051381:Rats; D017207:Rats, Sprague-Dawley; D011959:Receptors, Estradiol / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*
chemical_list: D003280:Contraceptives, Oral, Synthetic; D011959:Receptors, Estradiol; D011980:Receptors, Progesterone; D016912:Levonorgestrel