Acute effects of unilateral ovariectomy on follicular development in the cyclic hamster

摘要

Summary. Hamsters were hemispayed at 09:00 h on Day 3 of the cycle (Day 1 = ovulation) and were killed 1 h after injection of [3H]thymidine at 09:00, 12:00, 17:00 or 22:00 h. Unilateral ovariectomy had no effect on the number of Stage 1 or Stage 2 follicles, but there were significantly fewer Stage 3 follicles between 10:00 and 13:00 h. This decrease was not encountered in intact hamsters and was reflected in an increase in the number of Stage 6 (antral) follicles. At 13:00 h there was no difference in the number of atretic follicles between the experimental and control groups. It is concluded that preantral follicles with 6–7 layers of granulosa cells were recruited within 4 h after unilateral ovariectomy and transformed into antral follicles.