At 18 days of postnatal age. At this later phase, the frequency of cells demonstrating apoptotic condensation of the nucleus was greater than that in the 8-day-old testis (Table 1). The frequency of apoptosis among cells in stages IX-I was significantly higher than in the case of stages II-VI (Table 1). The apoptotic cells were identified as midpachytene spermatocytes (Fig. 1C) in stages VII-VIII and as type A spermatogonia in stages IX-I. In association with stages II-VI, only a few early pachytene spermatocytes were observed to undergo apoptosis, and no apoptotic intermediate or type B spermatogonia were present. In the case of pachytene spermatocytes, apoptotic condensation gave rise to bright, phase-negative spheres, a pattern clearly different from that seen with spermatogonia (Fig. 1C).
These same apoptotic pachytene spermatocytes were shown to be TUNEL positive (Fig. 1C’ and Table 1). paxil 40 mg
At 26 days of postnatal age. In the 26-day-old rat testis, the number of apoptotic cells per 1 ^m3 of tissue volume was also significantly higher than that in the 8-day-old testis (Table 1). On the other hand, the numbers of degenerating germ cells in the different stages of spermatogenesis per 1 ^m3 of tissue volume were very similar to the corresponding values for 18-day-old testis (Table 1).