HETEROGENEITY OF CELL-POPULATIONS THAT CONTRIBUTE TO THE FORMATION OF PRIMORDIAL FOLLICLES IN RATS
HETEROGENEITY OF CELL-POPULATIONS THAT CONTRIBUTE TO THE FORMATION OF PRIMORDIAL FOLLICLES IN RATS
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DOI：
10.1095/biolreprod47.3.466
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发表时间：
1992-09-01
影响因子：
3.6
通讯作者：
HIRSHFIELD, AN
中科院分区：
文献类型：
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作者：
HIRSHFIELD, AN
为了研究导致原始卵泡形成的事件，从妊娠第 14-19 天 (e14-e29) 开始，对怀孕大鼠连续输注 [H-3] 胸苷 (3H-TdR)，并持续 48-120 小时。收集幼崽的卵巢并制备塑料包埋的组织切片用于放射自显影。放射自显影照片显示，在发育中的卵巢的核心内有大量细胞，从 e14 一直到出生当天，这些细胞都保持有丝分裂不活跃（未能结合标签）。这些未标记的细胞产生了第一个卵泡的颗粒细胞，这些卵泡位于卵巢的髓质中，并且是第一个开始生长的。未标记的细胞似乎对后来在卵巢皮质区域形成的卵泡的形成没有贡献。当在妊娠晚期开始输注 3H-TdR 时，一小部分生殖细胞会掺入标签，但绝大多数生殖细胞并未掺入标签。标记的生殖细胞被认为代表那些发育滞后的生殖细胞（尚未进入减数分裂）。产后第一周卵巢组织发生完成后，发现未标记的卵母细胞集中在卵巢核心，包围在最早生长的卵泡中；标记的卵母细胞仅存在于卵巢皮质中微小的静止原始卵泡内。这些观察结果为长期存在但迄今为止未经检验的有关早期卵泡发生的假设提供了一些经验支持：开始生长的第一个卵泡在质量上与卵巢中剩余的卵泡不同，并且原始卵泡开始按照它们最初形成的顺序生长。
To study the events that lead to the formation of primordial follicles, pregnant rats were given continuous infusions of [H-3]thymidine (3H-TdR) beginning on Days 14-19 of pregnancy (e14-e29) and continuing for 48-120 h. Ovaries from the pups were collected and plastic-embedded histological sections were prepared for autoradiography. The autoradiographs revealed that within the core of the developing ovary were a large number of cells that remained mitotically inactive (failed to incorporate label) from e14 through the day of birth. These unlabeled cells gave rise to the granulosa cell of the first follicles that formed, were located in the medulla of the ovary, and were the first to begin growth. The unlabeled cells did not appear to contribute to the formation of the follicles that formed later in the cortical region of the ovary. When 3H-TdR infusion was begun during late pregnancy, a small subset of the germ cells incorporated label, although the vast majority did not. The labeled germ cells are presumed to represent those that were lagging in their development (had not yet entered meiosis). After ovarian histogenesis was completed during the first week postpartum, the unlabeled oocytes were found concentrated in the core of the ovary, enclosed in the earliest growing follicles; labeled oocytes were found exclusively in the cortex of the ovary, within tiny, quiescent primordial follicles. These observations provide some empirical support for long-held, but heretofore untested, hypotheses concerning early folliculogenesis: that the first follicles that begin to grow are qualitatively different from the remaining follicles in the ovary and that primordial follicles begin to grow in the order in which they were first formed.