Catechol estrogens stimulate synthesis of prostaglandins in the preimplantation rabbit blastocyst and endometrium

The influence of estradiol-17 beta (E2) or catechol estradiols [4-hydroxyestradiol-17 beta (4-OH-E2) or 2-hydroxyestradiol-17 beta (2-OH-E2)] on prostaglandin (PG) production in the rabbit blastocyst and endometrial cell in vitro on Day 6 of pregnancy (144 h postcoitum) was studied. Blastocysts (4-6) were incubated in 1 ml of RPMI-1640 medium for a total period of 8 h. Media were changed every 2 h and stored at -80 degrees C. E2, 4-OH-E2 or 2-OH-E2 at various concentrations were added during the second and fourth periods, while the vehicle was added during the first and third periods. Single cell suspensions of endometrial tissues in 0.5 ml of RPMI-1640 were incubated for 2 h with and without estrogens. The media and cells were separated and stored at -80 degrees C. PGs were determined by radioimmunoassay. The results for blastocyst were expressed as the cumulative release of PGs over a period of two 2-h incubations of the same experimental conditions (pg/blastocyst per 4 h). The release of PGs from the blastocyst was not influenced by 8.8 microM of 4-OH-E2, whereas 44 microM of this steroid stimulated the release of PGE-A by about 25% and PGF by 59% (P less than 0.05) over the vehicle-treated controls. The release of PGE-A and PGF in the presence of 44 microM of 2-OH-E2 was stimulated by about 60% and 37%. On the other hand, E2 at any concentration, either showed none or inhibitory effects on the release of PGs from the blastocyst.(ABSTRACT TRUNCATED AT 250 WORDS)