Influence of follicular components on oocyte meiosis in vitro.

Oocytes and follicular components obtained from ovaries recovered from mature Hereford cows at slaughter were used to determine follicular influence on oocyte maturation. Some oocytes were fixed immediately to determine the stage of maturation. The remaining oocytes were cultured for 32 to 34 hr in various environments to determine the influences of the granulosum and follicular fluids on meiotic changes. All noncultured oocytes had dictyate nuclei except one in premetaphase. Oocytes cultured in 50 or 100% follicular fluid or in contact with stratum granulosum cells showed some meiotic inhibition both before and after germinal vesicle breakdown (GVB). The least resumption of meiosis occurred in oocytes cultured in their intact follicles.