REGULATION OF CYCLOOXYGENASE-2 AND PROSTAGLANDIN-F SYNTHASE GENE-EXPRESSION BY STEROID-HORMONES AND INTERFERON-TAU IN BOVINE ENDOMETRIAL CELLS

Estradiol (E2) and progesterone are responsible for regulating PG synt hesis in the endometrium during the estrous cycle and interferon- tau (IFN-tau) alters PG synthesis during early pregnancy in ruminants. In this study, we examined the effects of these steroid hormones and reco mbinant bovine IFN-tau (rbIFN-tau) on PG production and on cyclooxygen ase-2 (COX-2) and PG F (PGF) synthase (PGFS) gene expression in isolat ed endometrial cells. E2 decreased both PGF(2 alpha) and PG E-2 (PGE(2 )) whereas progesterone increased PGF(2 alpha) secretion in epithelial cells. Steroid hormones had no effect on PG production in stromal cel ls. rbIFN-tau attenuated both PGF(2 alpha) and PGE(2) production in ep ithelial cells and enhanced their production, and the ratio of PGE(2) to PGF(2 alpha), in stromal cells. Northern blot analysis showed that E2 and rbIFN-tau decreased COX-2 messenger RNA (mRNA) levels in epithe lial cells. Conversely, rbIFN-tau increased COX-2 mRNA in stromal cell s. Furthermore, rbIFN-tau decreased PGFS mRNA in both cell types and t his was associated with the increase in PGE(2)/PGF(2 alpha) ratio. The se results show that the regulation of PG synthesis by steroid hormone s is different in endometrial epithelial and stromal cells in vitro. T he attenuation of PGF(2 alpha) secretion from epithelial cells and inc reased PGE(2) production in stromal cells by rbIFN-tau are modulated b y steroid hormones.