Shibata N, Hamaguchi S
Department of Biology, Niigata University, Japan.
J Exp Zool. 1988 Jan;245(1):71-7. doi: 10.1002/jez.1402450111.
The origin of the oocyte-like cells (testis-ova) induced by the administration of estradiol in the testis of the fish, Oryzias latipes, was examined by light and electron microscopy. A small number of testis-ova at the zygotene stage was seen on the sixth day after the beginning of treatment with estradiol, and on the 12th day testis-ova at the pachytene and diplotene stages were observed. Ultrastructural observations revealed that the testis-ova at the zygotene stage were organized as cysts and that all testis-ova within a given cyst developed synchronously. The number of these testis-ova in each cyst varied but cysts containing 16-20 or 26-30 testis-ova were most frequently observed. Spermatogonia of O. latipes are classified morphologically into two types: the type A and the type B spermatogonia (Grier, '76 Cell Tissue Res., 168:419-431). Type A spermatogonia, which were separated from each other by Sertoli cells, were of the stem type and type B spermatogonia appeared to divide clonally 9-10 times in each cyst before entering meiosis. The present observations on zygotene testis-ova indicate that the testis-ova originate from type B spermatogonia which have divided clonally four or five times, suggesting that male germ cells remain sexually bipotent through the early stages of development of type B spermatogonia.
通过光学显微镜和电子显微镜检查，研究了在青鳉鱼睾丸中施用雌二醇诱导产生的卵母细胞样细胞（睾丸卵）的起源。在用雌二醇开始治疗后的第6天，观察到少数处于偶线期的睾丸卵，在第12天观察到处于粗线期和双线期的睾丸卵。超微结构观察显示，处于偶线期的睾丸卵形成囊肿，并且给定囊肿内的所有睾丸卵同步发育。每个囊肿中这些睾丸卵的数量各不相同，但最常观察到含有16 - 20个或26 - 30个睾丸卵的囊肿。青鳉鱼的精原细胞在形态上分为两种类型：A型精原细胞和B型精原细胞（格里尔，《细胞与组织研究》，1976年，第168卷：419 - 431页）。A型精原细胞被支持细胞彼此隔开，属于干细胞类型，B型精原细胞在每个囊肿中似乎在进入减数分裂之前进行9 - 10次克隆分裂。目前对偶线期睾丸卵的观察表明，睾丸卵起源于已经进行了四到五次克隆分裂的B型精原细胞，这表明雄性生殖细胞在B型精原细胞发育的早期阶段保持性双能性。
