Intracellular regulation of endometrial PGF(2a) and PGE(2) production in dairy cows during early pregnancy and following treatment with recombinant interferon-tau

Objectives were to examine how the conceptus and recombinant bovine interfe ron-tau (rbIFN-tau) regulate intracellular components of the PGF(2a) synthe tic pathway and to determine if arachidonic acid (AA) is limiting in endome trial tissue of pregnant cows. In Experiment 1, uteri were collected from e ither cyclic or pregnant dairy cows on Day 17 post-estrus. Intercaruncular explants were dissected and incubated for 60 min to quantify PGF(2a) produc tion in response to oxytocin (10(-6) M), A23187 (10(-5) M), melittin (10(-5 ) M), and phorbol 12, 13 dibutyrate (PDBu, 10(-6) M). Additional explants f rom the same cows were incubated for 24 h with and without AA. Oxytocin and A23187 did not stimulate PGF(2a) in explants from either cyclic or pregnan t cows. Both PDBu, melittin, and A23187 + melittin stimulated PGF(2a) produ ction in explants of cyclic cows, but not in explants of pregnant cows. The addition of AA to explant cultures for 24 hr did not increase PGF(2a) prod uction during a subsequent 60-min incubation. In Experiment 2, explants wer e collected from cows that received intrauterine infusions of either BSA (1 .9 mg/1.2 ml) or rbIFN-tau (0.2 mg rbIFN-tau + 1.7 mg BSA/1.2 ml) twice a d ay from Days 14 to 17 of the estrous cycle. Treatments of rbIFN-tau attenua ted PGF(2a) secretion induced by in vitro PDBu and A23187 treatments. Howev er, rbIFN-tau treatment in vivo had no effect on the in vitro induction of PGF(2a) secretion by melittin. IFN-tau may regulate the PGF(2a) synthetic p athway by reducing activity of PKC or PKC mediated events. (C) 2000 Elsevie r Science Inc. All rights reserved.