Fraile B, Sáez F J, Paniagua R
Department of Cell Biology and Genetics, University of Alcalá de Henares, Alcalá de Henares (Madrid), Spain.
J Morphol. 1990 Apr;204(1):89-101. doi: 10.1002/jmor.1052040110.
Ultrastructural examination of the marbled newt (Triturus marmoratus) testis throughout the annual cycle revealed that during the period of testicular quiescence (November-February), primordial germ cells proliferate within cords of filament-rich epithelial cells that will become follicular cells (FCs). Fibroblast-like cells surround the FCs and form the lobule-boundary interstitial cells (ICs). During the period of germ cell development from primordial germ cells to round spermatids (March-June), the FCs surrounding the developing germ cells contain scanty cytoplasm with abundant rough endoplasmic reticulum and scarce filaments. With spermatid elongation (July-August), the FC size grows, its nucleus becomes irregularly outlined, and its cytoplasm displays abundant smooth endoplasmic reticulum, residual bodies, lipid droplets, and large vacuoles. After spermatozoon release by the FCs (August-September), the adjacent ICs increase their size and transform into Leydig cells with abundant smooth endoplasmic reticulum, mitochondria with tubular cristae, and lipid droplets. During the period of testicular quiescence (November-February), the Leydig cells undergo involution, eventually developing the morphological attributes of mesenchymal cells. Intermingled among these cells, cords of filament-rich cells are observed. During this period of the cycle, spermatozoon cysts supported by FCs are present. At the beginning of the germ cell proliferation period (March), these spermatozoa are released, and the adjacent ICs undergo a transformation into Leydig cells similar to those observed in August-September. Maturation and involution of ICs occur when testosterone levels are known to be rising and falling, respectively.
对大理石纹蝾螈（Triturus marmoratus）睾丸全年周期的超微结构检查显示，在睾丸静止期（11月至2月），原始生殖细胞在富含细丝的上皮细胞索内增殖，这些上皮细胞将成为滤泡细胞（FCs）。成纤维细胞样细胞围绕滤泡细胞并形成小叶边界间质细胞（ICs）。在生殖细胞从原始生殖细胞发育为圆形精子细胞的时期（3月至6月），围绕发育中生殖细胞的滤泡细胞含有少量细胞质，内质网丰富，细丝稀少。随着精子细胞伸长（7月至8月），滤泡细胞大小增加，细胞核轮廓不规则，细胞质显示丰富的滑面内质网、残余体、脂滴和大液泡。滤泡细胞释放精子后（8月至9月），相邻的间质细胞体积增大并转化为具有丰富滑面内质网、管状嵴线粒体和脂滴的睾丸间质细胞。在睾丸静止期（11月至2月），睾丸间质细胞退化，最终发展为间充质细胞的形态特征。在这些细胞中可观察到富含细丝的细胞索。在周期的这个时期，存在由滤泡细胞支持的精子囊肿。在生殖细胞增殖期开始时（3月），这些精子被释放，相邻的间质细胞经历转化，成为类似于8月至9月观察到的睾丸间质细胞。间质细胞的成熟和退化分别发生在已知睾酮水平上升和下降时。
