dinoprost and afimoxifene

Some of the isoflavonoids present in human diet as well as in urine are expected to exert biologic effects as they have been reported to bind to estrogen receptors and to be estrogenic in other species. This report describes the in vitro assessment of estrogenic effects of isoflavonoids using human endometrial cells and tissue. The relative estrogenic potencies (EC50 values) of estradiol, 3 dietary isoflavonoids (coumestrol, genistein and daidzein) and one of their metabolites (equol), were estimated by using a recently developed multiwell plate in vitro bioassay based on the estrogen-specific enhancement of alkaline phosphatase (AlkP) activity in human endometrial adenocarcinoma cells of the Ishikawa-Var I line. The maximal AlkP activity elicited by the isoflavonoids tested was as high as that achieved with estradiol and their effects were suppressed by the antiestrogens 4-hydroxytamoxifen and ICI 164,384. These results indicate that estradiol and the isoflavonoids exert their effects on AlkP by similar interactions with the estrogen receptor, with potencies depending on binding affinities. The estrogenic effect of equol was confirmed by another in vitro bioassay, based on the estrogen-stimulated enhancement of prostaglandin F2 alpha output by fragments of human secretory endometrium.

Topics: Adenocarcinoma; Alkaline Phosphatase; Biological Assay; Chromans; Coumestrol; Dinoprost; Endometrial Neoplasms; Endometrium; Equol; Estradiol; Female; Genistein; Humans; Isoflavones; Polyunsaturated Alkamides; Tamoxifen; Tumor Cells, Cultured

Dehydroepiandrosterone sulfate significantly increased prostaglandin F2 alpha output by fragments of human secretory endometrium during the first and second 24-hour periods of incubation in Ham's F-10 medium containing 10% charcoal-treated calf bovine serum. The effects of dehydroepiandrosterone sulfate were noted at 10(-6) mol/L concentrations, which are close to the normal plasma levels of this compound. For the purpose of comparison, the effects of estradiol at 10(-8) mol/L and those of unconjugated dehydroepiandrosterone, dehydroepiandrosterone acetate, 5-androstene-3 beta, 17 beta-diol, or 5 alpha-dihydrotestosterone were evaluated at 10(-8) to 10(-8) mol/L concentrations in parallel experiments. All of the delta 5-C19 steroids tested enhanced prostaglandin F2 alpha output at 10(-6) mol/L but not at 10(-8) mol/L; 5 alpha-dihydrotestosterone was inactive at 10(-6) mol/L but showed a stimulatory effect at 10(-5) mol/L in two experiments. The stimulation of prostaglandin F2 alpha production by the adrenal steroids was significantly reduced by the antiestrogen 4-hydroxytamoxifen at 10(-6) mol/L (a finding consistent with the reported utilization of the estrogen receptor for their actions on other systems) but was not affected by the antiandrogen 4-hydroxyflutamide at 10(-6) mol/L. Progesterone (10(-7) mol/L) also lowered the effects of dehydroepiandrosterone (10(-6) mol/L) and 5-androstene-3 beta,17 beta-diol (10(-6) mol/L), as well as those of estradiol (10(-8) mol/L). delta 5-C19 steroids at 10(-6) mol/L levels did not antagonize the effect of 10(-8) mol/L estradiol, whereas 5 alpha-dihydrotestosterone reduced it by 50% at these concentrations. The significant effect of 5 alpha-dihydrotestosterone points to potential antiestrogenic effects of the C19 compounds that may be manifested in vivo at particular C19/estradiol concentration ratios. The demonstration of direct estrogenic effects of delta 5-C19 steroids, which are not significantly converted to estrogens in vivo, justifies their use in estrogen replacement preparations and indicates that aromatase inhibitors may not eliminate completely the stimulation of estrogen-responsive breast and endometrial tumors by the patient's adrenal steroids.

Topics: Androstanes; Androstenediol; Culture Techniques; Dehydroepiandrosterone; Dehydroepiandrosterone Sulfate; Dihydrotestosterone; Dinoprost; Endometrium; Estrogen Antagonists; Female; Humans; Prostaglandins F; Tamoxifen

Estradiol stimulation and progesterone inhibition of human uterine PGF2 alpha production were studied using in vitro preparations of endometrial tissue and cells. Measurement of PGF2 alpha levels in media from primary cultures of glandular epithelia and stoma revealed that basal outputs were similar in both cell types but could be increased by estradiol only in epithelial cells. Tamoxifen (Tam) and trans-4-hydroxy tamoxifen (OHTam) did not affect basal PGF2 alpha outputs by secretory endometrium in organ culture and by monolayer cultures of epithelial cells, but counteracted the stimulatory effects of estradiol in both systems. The almost pure antiestrogenic activity exhibited by OHTam was at least 10 times greater than that of Tam, suggesting that the estrogen-stimulated increases in uterine PGF2 alpha output are mediated by specific estrogen receptors. Fragments of endometrium also released lipocortin, a phospholipase A2-inhibiting protein believed to mediate inhibitory effects of glucocorticoids on prostaglandin production in several types of cells. Although dexamethasone increased lipocortin and decreased PGF2 alpha output in secretory endometria in vitro, progesterone inhibited both lipocortin and PGF2 alpha output. The mechanisms by which P inhibits PGF2 alpha production remain to be elucidated.

Topics: Annexins; Cells, Cultured; Dinoprost; Endometrium; Epithelium; Estradiol; Female; Glycoproteins; Humans; Prostaglandins F; Tamoxifen

It has been previously reported that neither an antiestrogen, actinomycin D, nor cycloheximide inhibited estradiol (E2)-stimulated elevations in uterine prostaglandin F2 alpha (PGF2 alpha) production in ovariectomized rats, suggesting that in contrast to other steroid-initiated events, this effect on PGF2 alpha may not involve receptor-mediated transcription-dependent actions of E2. To eliminate indirect influences, the ability of antiestrogens to affect PGF2 alpha output was reevaluated during incubations of human secretory endometrium and in cultures of epithelial cells derived from glands isolated from proliferative and secretory tissues. In these preparations, which respond to E2 with marked elevations in PGF2 alpha output, tamoxifen and its metabolite trans-4-monohydroxytamoxifen acted as virtually pure antagonists, counteracting the E2 effect while failing to influence basal PGF2 alpha output. Consistent with its effects on other estrogen-mediated end points, trans-4-monohydroxytamoxifen was at least 10 times more potent than tamoxifen, eliminating, at a 10(-6) M concentration, almost completely the stimulatory effect of 10(-8) M E2 on PGF2 alpha production by both endometrial fragments and monolayers of epithelial cells.

Topics: Cells, Cultured; Dinoprost; Endometrium; Epithelial Cells; Epithelium; Estradiol; Estrogen Antagonists; Female; Humans; Prostaglandins F; Tamoxifen