CONTROL OF SERTOLI CELL NUMBER AND TESTICULAR SIZE

目的是了解精子发生和精子百分率是如何 生产受到管制或调节。生殖细胞的退化是一种 精子发生的普遍现象，降低了精子发生的理论值 动物和人类的每日精子生成量。损失高达75% 理论值出现在精母细胞形成过程中。然而，几乎没有什么是 已知其机制、原因、与体细胞的关系 人口，或其预防。为了评估退行性变和 每日产生精子的干细胞数量，包括数量和 放射自显影研究将使用光学显微镜进行。我们有 表明精原细胞数量的变化在很大程度上是 用于公马每日精子产量的季节性变化。本研究 将确定A精原细胞数量的增加是否可以用 干细胞数量增加或亚型间变性减少 精原细胞。骨髓间充质干细胞数量和退行性变的评价 精原细胞在不同季节，其中每日精子的差异 已知的生产是自然发生的，将揭示在哪些方面 精母细胞生成是灵活的，并可能受到干预。 长期的标签实验应该有助于评估“储备”。 干细胞的概念，因为如果这些细胞处于休眠状态，就不应该标记它们 在精子生成活跃的睾丸中。两者之间的相互关系 精原细胞和支持细胞或间质细胞群 已评估。通过放射自显影和定量研究， 对支持细胞和间质细胞的有丝分裂进行评估。这个 每日精子产量、干细胞数量、 生殖细胞变性、支持细胞和间质细胞群大小 细胞，荷尔蒙浓度将被评估。电子显微镜 将被用来支持光学显微镜。季节性退化的 种马睾丸似乎在评估相互关系方面很有用。 老化的人类睾丸的变化。两者都表现出精子减少 产量，精原细胞数量减少，精原细胞数量减少 支持细胞和间质细胞。老年人的游戏功能 随着越来越多的人活得更长，睾丸变得越来越重要。了解以下内容 如何调节精子产生率对人类家庭也是有用的 规划涉及少精子症男性和避孕策略的项目。

The objective is to understand how spermatogenesis and the rate of sperm production are regulated or modulated. Degeneration of germ cells is a common phenomenon of spermatogenesis which reduces theoretical values of daily sperm production in both animals and men. As high as 75% loss of theoretical values occurs during spermatocytogenesis. However, little is known about its mechanism, causes, relationship to somatic cell populations, or its prevention. To evaluate the roles of degeneration and number of stem cells on daily sperm production, both quantitative and autoradiographic studies will be conducted using light microscopy. We have shown that changes in numbers of A spermatagonia are largely responsible for seasonal variation in daily sperm production in stallions. This study will determine if increased number of A spermatogonia can be explained by increased number of stem cells or by less degeneration among subtypes of spermatogonia. Evaluation of stem cell number and degeneration of spermatogonia in different seasons, in which differences in daily sperm production are known to occur naturally, will reveal which aspects in spermatocytogenesis are flexible and possible amenable to intervention. The long-term labelling experiment should aid in evaluating the "reserve" stem cell concept as these cells should not be labelled if they are dormant in testes with active spermatogenesis. Interrelationships between spermatogonia and the Sertoli cell or Leydig cell population will be evaluated. Through autoradiographic and quantitative studies, the role of mitosis on number of Sertoli cells and Leydig cells will be evaluated. The temporal relationships between daily sperm production, stem cell number, germ cell degeneration, size of populations of Sertoli cells and Leydig cells, and hormone concentrations will be evaluated. Electron microscopy will be used to support light microscopy. The seasonally regressed stallion testis appears to be useful in evaluating the interrelationships of changes in the aging human testis. Both exhibit reduced sperm production rate, reduced numbers of spermatogonia, and reduced numbers of Sertoli cells and Leydig cells. The gametic function of the aging human testis is becoming more important as more people live longer. Knowledge of how sperm production rate may be regulated also is useful to human family planning programs involving oligospermic men and contraception strategies.