Abstract: | Estradiol-17β selestively stimulated the release of PGF from separated glandular but not stromal cells of human secretory endometrium (p<0.025) but had no effect on PGF release from either type of cells obtained from proliferative endometrium. PGE release was not affected by estradiol-17β. Actinomycin D did not antagonise the effect of estradiol-17β on PGF release from secretory, glandular cells. Basal release of PGF from these cells was stimulated by actinomycin D alone (100 ng/ml) (p<0.025) and PGE release stimulated in the presence of estradiol-17β. Actinomycin D had no effect on PGF or PGE release from proliferative endometrium. These findings suggest that estradiol-17β stimulates PGF release by a mechanism that does not affect PGE release and which is not dependent on the synthesis of new protein. The basal release of PGF and PGE by glandular cells of secretory endometrium in vitro is regulated by protein/proteins which reduce PG release. |