AGE EFFECTS ON NUMBER AND FUNCTION OF SERTOLI CELLS AND SPERMATOGONIA

越来越多的证据表明睾丸激素可以维持 精子发生通过这种类固醇与 支持细胞。 因此，生理情况，导致一个 睾丸支持细胞周围雄激素浓度减少，或 导致这些细胞的反应能力下降， 睾丸激素会导致睾丸分泌减少 精子 在雄性大鼠中，睾丸老化的特征是 精子产量的下降和睾丸激素的减少 Leydig细胞的生产。 我们认为，在老年大鼠， T细胞生成减少导致睾丸内 睾酮浓度，因此，减少支持 细胞功能 虽然对生精细胞的影响 睾丸支持细胞功能低下，数量减少，或者可能 干精原细胞功能降低。 概述的实验 在这个应用程序中将测试这个假设。 首先，我们会 确定年龄和不同睾丸内 睾酮浓度对大鼠睾丸数量和功能的影响 支持细胞。 接下来，我们将研究年龄对 干精原细胞分裂的数量和速度。 最后， 我们将研究睾丸内睾酮 浓度影响干精原细胞的数量和功能 年轻和年老的老鼠。

There is mounting evidence that testosterone acts to maintain spermato-genesis through the interaction of this steroid with Sertoli cells. Thus, physiological situations which lead to a diminution of androgen concentration around Sertoli cells, or which lead to a reduction in the ability of these cells to respond to testosterone, could lead to a reduced production of testicular spermatozoa. In the male rat, testicular aging is characterized by a decline in sperm production and by a decrease in testosterone production by Leydig cells. We suggest that in the aged rat, decreased T production leads to decreased intratesticular testosterone concentration, and therefore, to diminished Sertoli cell function. While the consequences to spermatogenic cells of a hypofunctional Sertoli cells and a reduced number, or possibly reduced function, of stem spermatogonia. The experiments outlined in this application will test this hypothesis. First, wee will determine the effect of age and different intratesticular testosterone concentrations on the number and functions of rat Sertoli cells. Next, we will examine the effect of age on the number and rate of cell division of stem spermatogonia. Finally, we will examine how different intratesticular testosterone concentrations affect the number and function of stem spermatogonia in young and old rats.