Interferon-Tau Suppresses Prostaglandin F2a Secretion Independently of the Mitogen-Activated Protein Kinase and Nuclear Factor k B Pathways1

Pregnancy is established in ruminants through inhibitory ac-tions of interferon (IFN)-t on the release of prostaglandin F2a (PGF), which allows the corpus luteum to survive and continue to produce progesterone. Experiments were designed to 1) de-lineate the signal transduction pathway coordinating the synthe-sis of PGF, 2) determine how rapidly recombinant bovine (rb) IFN-t attenuated phorbol ester (PDBu)-induced secretion of PGF, and 3) establish the site at which rbIFN-t attenuates the secretion of PGF in cultured bovine endometrial (BEND) cells. BEND cells were untreated (control) or treated for 5, 10, 60, 180, or 300 min with PDBu (100 ng/ml), rbIFN-t (50 or 500 ng/ml), PDBu 1 rbIFN-t, or PDBu 1 PD98059 (MEK-1 inhibi-tor; 50 mM). Secretion of PGF was induced (P, 0.0001) by PDBu within 180 min, but induction was inhibited 74 % by th