PARENT SESSION

(W561) QUANTITATIVE INHIBITION OF PROSTAGLANDIN-F2 ALPHA SYNTHESIS: BASIS FOR A BIOASSAY TO MEASURE BOVINE INTERFERON-TAU ACTIVITY.

Binelli, Mario¹, Marques, Vanessa², Bertan, Claudia¹, Miguez, Patricia¹, Miglino, Maria ², Meirelles, Flavio¹, ¹ University of Sao Paulo, Pirassunuga, Brazil² University of Sao Paulo, Sao Paulo, Brazil

ABSTRACT- In cattle, maternal recognition of pregnancy is mediated through interferon-tau (IFN-). The IFN- is a conceptus secretory protein which main action is to block production of prostaglandin-F2 (PGF) in the endometrium. Activity of IFN- is usually measured indirectly, via an antiviral assay. It s proposed that a more adequate assay should measure the antiluteolytic activity of IFN-, which is the ability to inhibit production of PGF. Objective was to verify whether IFN- could quantitatively inhibit phorbol-ester induced synthesis of PGF in a line of bovine endometrial cells (BEND cells). In experiment 1, BEND cells were platted on 48-well plates and treated in triplicate with 0, 6.25, 12.5, 25, 50, 100 or 200 ng/ml of 12, 13-phorbol dibutyrate (PDBu) for 6 h in three independent repetitions. Concentrations of PGF in culture medium were measured by radioimmunoassay. The PDBu stimulated PGF synthesis in a concentration-dependent manner (P<0.01). Twenty five ng/ml PDBu elicited sub-maximal synthesis of PGF. In experiment 2, BEND cells were treated in triplicate with 25 ng/ml PDBu associated with 0, 0.39, 0.78, 1.56, 3.13, 6.25, 12.5 or 25 ng/mL recombinant bovine IFN- for 6 h in three independent repetitions. The IFN- inhibited PDBU-stimulated synthesis of PGF in a concentration-dependent manner (P<0.01). Concentration of IFN which caused 50% inhibition was between 0.39 and 0.78 ng/mL. It was concluded that IFN- has the ability to quantitatively inhibit PDBu-induced synthesis of PGF. It is expected that the antiluteolytic activity in biological fluids of interest can be measured using a similar assay system.

KEY WORDS: Prostaglandin F2, Interferon-, Bioassay, Cattle