CONTROL OF SERTOLI CELL NUMBER AND TESTICULAR SIZE

目的是了解精子发生和精子率 生产受到控制或调节。 生殖细胞的退化是一种 精子发生的一种常见现象， 动物和人类的精子日产量 高达75%的损失 理论值发生在精母细胞发生期间。 然而， 了解其机制，原因，与体细胞的关系 人口，或预防。 评估变性的作用， 干细胞数量对每日精子产量的影响，包括数量和 使用光学显微镜进行放射自显影研究。 我们有 结果表明，A型生精细胞数量的变化在很大程度上是 种马每日精子产量的季节性变化。 本研究 将确定A型精原细胞数量的增加是否可以解释为 增加干细胞数量或减少亚型间的退化 精原细胞 评估干细胞数量和变性， 精原细胞在不同的季节，其中每天精子的差异 生产是自然发生的，将揭示哪些方面， 精子细胞发生是灵活的，可能易于干预。 长期标签实验应有助于评估“储备” 干细胞概念，因为如果这些细胞处于休眠状态，则不应对其进行标记 在精子发生活跃的睾丸中。 之间相互关系 精原细胞和支持细胞或间质细胞群将被 评估。 通过放射自显影和定量研究， 将评价有丝分裂对支持细胞和间质细胞数量的影响。 的 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的大小 细胞和激素浓度将被评估。 电子显微镜 将用于支持光学显微镜。 季节性回归 种马睾丸似乎是有用的，在评估的相互关系 老化的人类睾丸的变化。 两个人的精子都减少了 生产率，精原细胞数量减少， 支持细胞和间质细胞。 老年人的配子功能 随着越来越多的人活得更长，睾丸变得越来越重要。 知识 如何调节精子生产率对人类家庭也是有用 规划涉及少精子症男性的方案和避孕策略。

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.