Surface plasmon resonance binding and Western blot data. Surface plasmon resonance binding data (A, B): oviduct fluid diluted 1/25 was injected on anti-osteopontin antibody (A) or anti- ANP A antibody (B) surface. The sensorgramms show an association phase (increasing response) during the 120 seconds injection of fluid, followed by a dissociation phase (decreasing response) studied for 120 seconds. Shown sensorgramms have been subtracted from the sensorgramms obtained on their reference surface. Western blot data (C, D): Osteopontin (C) and ANP A (D) protein expression in equine oviducts from stage 1 (emergence of the dominant follicle, lane 1), stage 2 (end of the follicular growth, lane 2) and stage 3 (preovulatory stage, lane 3).