Modulation of Uterine Phospholipase $A_2$ Activity by Estradiol During the Delayed Implantation Process in Rats

흰쥐의 착상기간중 Estradiol이 자궁의 Phospholipase $A_2$ 활성도에 미치는 영향

  • Yoon, Mi-Chung (Endocrine Laboratory, College of Medicine, Yonsei University) ;
  • Kim, Chang-Mee (Endocrine Laboratory, College of Medicine, Yonsei University) ;
  • Choe, Rim-Soon (Department of Biology, College of Science, Yonsei University) ;
  • Ryu, Kyung-Za (Department of Pharmacology, College of Medicine, Yonsei University)
  • 윤미정 (연세대학교 의과대학 내분비연구실) ;
  • 김창미 (연세대학교 의과대학 내분비연구실) ;
  • 최임순 (연세대학교 이과대학 생물학과) ;
  • 유경자 (연세대학교 의과대학 약리학교실)
  • Published : 1991.12.30

Abstract

The present study was performed to determine whether estradiol, via cAMP mediation, induces prostaglandin synthesis by modulating phospholipase $A_2$ activity which hydrolyzes phospholipids into arachidonic acids, a precursor for prostaglandin synthesis, during the implantation process in rats. Uterine phospholipase $A_2$ activity was elevated on day 5 of pregnancy when implantation normally occurs in rats. Moreover, phospholipase $A_2$ activity was higher in the implant sites than in the non-implant sites of uterus on day 6. In delayed implantation model, phospholipase $A_2$ activity was increased at 12 hrs after estradiol administration and at 8 hrs after dbcAMP administration. In addition, higher activity of phospholipase $A_2$ was induced by the treatment of estradiol plus theophylline, compared with estradiol-only treated group. The simultaneous treatment of indomethacin with estradiol or dbcAMP did not alter phospholipase $A_2$ activity compared with estradiol or dbcAMP-only treated group although significant suppression was observed in uterine PGE and $PGF_{2{\alpha}}$ concentrations. These results suggest that estradiol or cAMP stimulates uterine phospholipase $A_2$ activity, thereby increasing prostaglandin synthesis during the implantation process in rats.