The only effects of recombinant follicle-stimulating hormone for ovulation induction in the pre-implantation period of rats

Arch Gynecol Obstet. 2007 Feb;275(2):99-105. doi: 10.1007/s00404-006-0236-x. Epub 2006 Sep 5.


Objective: The aim of this study was to evaluate the changes in follicular development, serum hormonal levels, and endometrium in the pre-implantation period of rats by using recombinant FSH (rFSH) without human chorionic gonadotropin (hCG).

Methods: Thirty female rats were studied in six groups of five specimens. Two groups determined as controls (groups 1 and 2). Two groups received constant doses of rFSH (groups 3 and 4) and other two decreasing doses (groups 5 and 6). One of the paired groups was mated. Uterus, ovaries, and blood samples were taken from non-mated groups (groups 1, 3, and 5) at the proestrus period and from mated groups (groups 2, 4, and 6) in the pre-implantation period.

Results: In non-mated groups antral follicles and corpus luteum periodicum and in mated groups antral follicles, corpus luteum periodicum, and corpus luteum graviditatis were increased in rFSH groups, especially in decreasing dose groups. Estradiol (E2) levels were increased and progesterone (P)/E2 ratio was significantly decreased in decreasing dose groups. Endometrium surface epithelium was columnar, irregular, and folded in rFSH groups. Endometrium glandular epithelium was cuboidal in all groups. In decreasing dose groups endometrial stroma was smooth and fibroblastic. Mitotic indices of endometrium surface, glandular epithelium, and stroma were significantly decreased in rFSH groups. Primary follicles and P levels showed no change.

Conclusion: It seems likely that decreasing doses of rFSH might be used in order to improve follicular development, although it has negative effects with E2 on endometrium in the pre-implantation period of rats.

MeSH terms

  • Animals
  • Dose-Response Relationship, Drug
  • Endometrium / drug effects*
  • Endometrium / pathology
  • Female
  • Follicle Stimulating Hormone / pharmacology*
  • Follicular Phase
  • Ovary / drug effects*
  • Ovary / pathology
  • Ovulation Induction*
  • Rats
  • Rats, Wistar
  • Recombinant Proteins / pharmacology


  • Recombinant Proteins
  • Follicle Stimulating Hormone