SEASONAL-CHANGES IN SPERMATOGENIC CELL DEGENERATION IN THE SEMINIFEROUS EPITHELIUM OF ADULT JAPANESE MACAQUES (MACACA-FUSCATA-FUSCATA)

The degenerating pattern of spermatogenic cells in the seminiferous tu bule of Japanese macaques was studied to clarify a relationship betwee n seasonal changes of reproductive performances and cytological findin gs in the Japanese macaque. For light microscopy, testis samples were obtained from five adult animals by biopsy in April (nonmating season) and October (mating season). For electron microscopy, specimens from four additional macaques were used. Degenerating cells were found in a ll steps of spermatogenesis. In stages I to V of the cycle of the semi niferous epithelium, morphologically atypical pachytene spermatocytes were observed in 14.7 and 10.0% of the cells in the nonmating and mati ng seasons, respectively, although the difference in percentage was no t significant. Mature spermatids with atypical features in those stage s occupied 59.6% of the cells in the nonmating season, which significa ntly decreased to 34.1% in the mating season. These results imply that the seasonal change of sperm production is related, at least in part, to the process of degeneration of the spermatogenic cells in this spe cies.