Bovine ovarian follicular fluid vitronectin content is influenced by the follicle size

Vitronectin was quantified in the follicular fluid aspirated from bovine follicles with diameters of 3 to 15 mm (as determined by ultrasonography) using a specific enzyme-linked immunosorbent assay (ELISA) validated for bovine vitronectin. The primary antibody was raised in rabbit against vitronectin purified from bovine plasma. Vitronectin quantified in serial dilutions of bovine plasma and ovarian follicular fluid was highly correlated with the volume of each sample assayed. In addition, known amounts of purified bovine vitronectin added to samples of plasma or follicular fluid were accurately recovered. Follicular fluid concentrations of vitronectin were positively correlated with the follicle diameter (r = 0.8; P < 0.01). These data indicate that bovine follicular fluid concentration of vitronectin is influenced by the stage of follicular development.