Figure 4. Peripubertal ovarian maturation in the mouse.

Schematic drawing showing antral follicle development in non-ovulating mice and the first two cycles after the first ovulation, and the corresponding Pub-scores from −5 to +8. The age of the animals is matched to the day of the first ovulation (PND-42 in the example; encircled). An ovarian section (stained with hematoxylin and eosin) showing corpora lutea of the current cycle (four day-old; CLp) with abundant apoptotic cells (arrows) and class F4 follicles. In accordance, a Pub-score of +4 is assigned and the first ovulation occurred at PND-39 (red box).