Foreman D
Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA.
Anat Rec. 1997 Mar;247(3):355-67. doi: 10.1002/(SICI)1097-0185(199703)247:3<355::AID-AR7>3.0.CO;2-T.
The male prairie dog (Cynomys ludovicianus) is an annual breeder with complete testicular regression between breeding periods. Knowledge of the seminiferous tubule cycle stages at all phases of the annual cycle is essential for evaluation of testicular effects of endogenous and exogenous hormones. Testis tubule diameter is directly correlated with testicular weight during the annual cycle. Seminiferous tubule stages found during testicular activity start with sperm release and round spermatids in the Golgi stage (I). Then they progress through the cap and acrosome stages (stages II to VI) until elongate spermatids are formed. During these stages preleptotene, leptotene and zygotene cells develop into pachytene cells which mature with the long spermatids (stage VII). Two distinct tubule associations (stages VIII, IX) follow during which the first and second meiotic metaphases occur. These stages are correlated with the middle and late phases of residual lobe retraction and condensation. The last stage (X) has final sperm development and is present with round spermatids that have no Golgi development. During regression changes are initially associated with the seminiferous tubule stages of active testes and end with relocation of Sertoli cell nuclei to a position above the basal layer of spermatogonia. Out of season testes are characterized by few spermatogonial mitoses and absence of viable spermatocytes. In recrudescent testes, Sertoli cell nuclei again become basal, spermatogonia resume mitoses and spermatocytes and spermatids progressively develop. After each cycle of proliferation of germ cells there is sloughing of the most differentiated spermatocytes and spermatids until the final tubule associations of the active testis are present.
雄性草原犬鼠（黑尾土拨鼠）是一年生繁殖动物，在繁殖期之间睾丸会完全退化。了解年度周期各阶段的生精小管周期阶段对于评估内源性和外源性激素对睾丸的影响至关重要。在年度周期中，睾丸小管直径与睾丸重量直接相关。在睾丸活动期间发现的生精小管阶段始于精子释放和处于高尔基体阶段（I）的圆形精子细胞。然后它们经过帽状和顶体阶段（II至VI阶段），直到形成伸长的精子细胞。在这些阶段，前细线期、细线期和偶线期细胞发育成粗线期细胞，这些细胞随着长形精子细胞成熟（VII阶段）。随后是两个不同的小管组合（VIII、IX阶段），在此期间发生第一次和第二次减数分裂中期。这些阶段与残余叶退缩和浓缩的中期和后期相关。最后一个阶段（X）有精子的最终发育，存在没有高尔基体发育的圆形精子细胞。在退化过程中，变化最初与活跃睾丸的生精小管阶段相关，最后支持细胞的细胞核重新定位到精原细胞基底层上方的位置。非繁殖季节的睾丸特征是精原细胞很少有有丝分裂，且没有活的精母细胞。在再生的睾丸中，支持细胞的细胞核再次回到基部，精原细胞恢复有丝分裂，精母细胞和精子细胞逐渐发育。在生殖细胞每次增殖周期后，最分化的精母细胞和精子细胞会脱落，直到活跃睾丸的最终小管组合出现。
