Chronological changes in sex steroids and prostaglandins receptor concentrations in rat endometrium during peri-implantation period
Takahashi, T.
Nihon Sanka Fujinka Gakkai Zasshi 41(9): 1463-1470
1989
ISSN/ISBN: 0300-9165 PMID: 2555426 Document Number: 341073
Successful completion of implantation requires coordinated functional synchronism of fertilized egg and endometrium. In the present study, these synchronized changes were analyzed by chronological changes in estradiol (E2) progesterone (P4) and prostaglandin E2 and F2.alpha. (PGE2, PGF2.alpha.) receptor (R) concentrations in various sites in rat endometrium during the peri-implantation period. Unilaterally pregnant horn prepared by tubal ligation was also used. The results obtained: Nuclear E2R (E2RN) increased in the first 5 days of the fertilized cycle but decreased after that in the pregnant horn. P4RN, on the other hand, continued to increase throughout the period studied. PGE2-R remained low until the 6th day but thereafter showed a rapid increase. PGF2.alpha.-R was significantly higher in the pregnant horn but showed a fall after day 6. Cyclooxygenase distribution, studied by 14C-indomethacin binding, showed an increase in the peri-implantation period. The synchronous changes required for successful implantation therefore, involve complex changes in steriods as well as the prostaglandin receptor concentration in the endometrium around the implantation tissue.