title: Testicular development in cynomolgus monkeys.
abstract: The testes from 136 male cynomolgus monkeys were examined histopathologically in order to investigate the relationship between the development of spermatogenesis and testis weight, age, and body weight. At Grade 1 (immature), Sertoli cells and spermatogonia were the only cell classes in the testis. At Grade 2 (pre-puberty), no elongated spermatids were observed in the testis, although a few round spermatids and small lumen formation were observed. At Grade 3 (onset of puberty), all classes of germ cells were observed in the testis, although seminiferous tubule diameters and numbers of germ cells were small. Slight debris in the epididymis was observed in almost all animals. At Grade 4 (puberty), almost complete spermatogenesis was observed in the seminiferous tubules and it was possible to ascertain the spermatogenesis stage as described by Clermont, although tubule diameters and numbers of germ cells were small. There was less debris in the epididymis than at Grade 3. At Grade 5 (early adult), complete spermatogenesis was observed in the seminiferous tubules. At Grade 6 (adult), complete spermatogenesis in the seminiferous tubules and a moderate or large number of sperm in the epididymis were observed. Moreover, sperm analysis using ejaculated sperm was possible. Logistic regression analysis showed that testis weight is a good indicator of testicular maturity.
authors.affiliation: Drug Safety Research Laboratories, Shin Nippon Biomedical Laboratories, Ltd., Kagoshima, Japan.
authors.forename: Emiko
authors.initials: E
authors.lastname: Haruyama
authors.forename: Masakazu
authors.initials: M
authors.lastname: Suda
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ayukawa
authors.forename: Koshiro
authors.initials: K
authors.lastname: Kamura
authors.forename: Megumi
authors.initials: M
authors.lastname: Mizutamari
authors.forename: Yojiro
authors.initials: Y
authors.lastname: Ooshima
authors.forename: Akihide
authors.initials: A
authors.lastname: Tanimoto
mesh_terms: D000367:Age Factors; D000818:Animals; D001835:Body Weight; D004822:Epididymis / Q000254:growth & development; D006651:Histocytochemistry; D016015:Logistic Models; D008252:Macaca fascicularis / Q000254:growth & development*; D008297:Male; D009929:Organ Size / Q000502:physiology; D012741:Sexual Maturation / Q000502:physiology*; D013091:Spermatogenesis / Q000502:physiology; D013737:Testis / Q000254:growth & development* / Q000502:physiology