Two-dimensional polyacrylamide gel electrophoresis map of bovine ovarian fluid proteins.

Molecular mechanisms underlying the cystic degeneration of ovarian follicles in the dairy cow have not been clarified yet. A useful approach for complementing endocrinological and clinical studies could be represented by the systematic analysis of the protein patterns in follicular and cystic fluid. With this aim, a two-dimensional polyacrylamide gel electrophoresis map of proteins contained in fluid from bovine ovarian follicles at different stages of development and from bovine ovarian cyst has been obtained. About 200 spots were detected after silver staining. Polypeptides from nine spots or series of spots have been identified by N-terminal sequencing, and further analysis of the map has been performed by gel comparison. Alpha-1-antitrypsin, albumin, serotransferrin and apolipoprotein A-I and A-IV were located on the map. Comparison between protein patterns revealed the differential expression of some spots among follicles of smaller diameter, follicles of larger diameter, and cysts. This could represent the first step toward the identification of proteins differentially expressed and associated with ovarian cyst development.