Ovine follicular fluid inhibits thymidine incorporation by 3T3 fibroblasts in vitro.

Abstract

The ability of antral follicular fluid obtained from sheep follicles to inhibit 3T3 fibroblasts maintained for 48 h in concentrations of fetal calf serum optimal for cell growth was examined. Addition of pooled follicular fluid to cultures resulted in a dose-dependent and reversible inhibition of [3H]thymidine incorporation. Serum from ovariectomized ewes, fetal calf serum, bovine inhibin, oestradiol-17 beta, testosterone, cortisol or progesterone were without effect over a range of doses. Treatment of pooled follicular fluid with charcoal-dextran did not reduce inhibitory activity which was only partly removed by heating at 85 degrees C. Fluid obtained from large follicles (greater than 5 mm) was more potent as an inhibitor than was fluid obtained from smaller (less than 5 mm) follicles. Gel chromatography of pooled fluid resolved two peaks of inhibitory activity associated with material of Mr approximately 180,000 and less than 10,000 respectively. No inhibitory activity was evident in fractions of serum from ovariectomized ewes chromatographed in an identical manner. These results indicate that ovine follicular fluid contains two components able to inhibit reversibly mitosis of 3T3 fibroblasts in vitro.