A Comparison of the Fluids From Small and Large Ovarian Follicles of the Pig

The concentration and composition of proteins in pooled pig serum and fluids from large, small and cystic ovarian follicles of the pig were compared by means of electrophoresis and gel-filtration. Follicular and cystic fluids contained lower concentrations of total protein than did pooled serum. The follicular fluids all contained more albumin plus alpha globulins, but less gamma globulins relative to serum. The majority of fluids from small follicles exhibited a fast-migrating alpha globulin which was absent in most fluids from large follicles; whereas the majority of fluids from large follicles exhibited a slowly-migrating alpha globulin not observed in fluids from most small follicles. Oocyte maturation occurred in vitro in media containing fluids from small follicles whose endogenous oocytes had been at the germinal vesicle stage. With one group of fluids, from large follicles containing immature oocytes when recovered, oocyte maturation was totally inhibited in vitro. The fluids from pig follicles at different physiological stages exhibit differences in their protein patterns, which may be related to oocyte maturation.