Hirshfield A N
Department of Anatomy, University of Maryland School of Medicine, Baltimore 21201, USA.
Environ Mol Mutagen. 1997;29(1):10-5.
Folliculogenesis is the lengthy process that results in the production of a species-specific, highly consistent number of follicles, which ripen during each reproductive cycle at precisely the appropriate time for ovulation. Certain features of folliculogenesis may have special implications for toxicologists studying effects of environmental mutagens on oocytes. Such features include the constantly changing geometry of the ovarian follicle, the great excess of developing follicles (most of which will degenerate rather than ovulate), the exponential nature of follicular growth, the acceleration of cell proliferation as follicular size increases, and the location of the principal feedback regulatory step at the penultimate stage of the developmental process. Because the ovary can respond quickly and completely to loss of homeostasis over the short term, damage from toxic insult may not be readily apparent. However, long-range fertility may nevertheless be impaired. The finite size of the follicular pool and the absence of feedback regulatory steps during the early stages of follicular growth render the ovary incapable of restoring the status quo among small and medium-sized follicles. This will eventually result in loss of fine control over the number of follicles that ripen and the regularity of the reproductive cycles and could reduce the overall duration of the fertile life span.
卵泡发生是一个漫长的过程，其结果是产生特定物种、数量高度一致的卵泡，这些卵泡在每个生殖周期的精确适当时间成熟以进行排卵。卵泡发生的某些特征可能对研究环境诱变剂对卵母细胞影响的毒理学家具有特殊意义。这些特征包括卵巢卵泡不断变化的几何形状、发育中的卵泡数量过多（其中大多数会退化而不是排卵）、卵泡生长的指数性质、随着卵泡大小增加细胞增殖的加速，以及主要反馈调节步骤位于发育过程的倒数第二阶段。由于卵巢在短期内可以对稳态丧失做出快速而完全的反应，因此毒性损伤造成的损害可能并不容易显现。然而，长期生育能力仍可能受到损害。卵泡池的有限大小以及卵泡生长早期缺乏反馈调节步骤，使得卵巢无法恢复中小卵泡之间的现状。这最终将导致对成熟卵泡数量和生殖周期规律性的精细控制丧失，并可能缩短生育寿命的总体时长。
