ABP AND THE REGULATION OF GERM CELL APOPTOSIS IN TESTIS

精子发生是雄激素依赖和雄激素结合的过程 蛋白质(ABP)是支持细胞的一种分泌产物，被认为是一种 雄激素对发育中的生殖细胞的调节作用。然而， 总部基地的确切行动模式尚不清楚。为了更好地理解 ABP的功能，从更广泛的意义上讲，雄激素在 精子发生的控制，我们研究了转基因小鼠表达 大量的ABP。这些动物表现出进行性的异常 精子发生和最终失去生育能力。为了解释一下 这一发现，我们假设ABP的长期生产过剩 改变增殖和退化(细胞凋亡)之间的平衡 通过改变生殖细胞内的类固醇激素环境 生精小管。这可能不仅涉及睾丸素，还包括 是具有生物活性的睾丸内代谢物双氢睾酮 和雌二醇。为了检验上述假设，我们建议确定 转基因动物产生的过量ABP对(1)-- 睾丸中的睾酮、双氢睾酮、雌二醇和 雄激素和雌激素受体。特异性放射免疫分析， 免疫细胞化学和原位杂交将用于实现 这个目标。(2)生殖细胞增殖和凋亡的动力学 在精子发生衰退之前和期间。流式细胞术和 在对两者进行特定标记后，将使用形态测量分析 增殖和凋亡的细胞。将通过IN检测到细胞凋亡 片段DNA的原位末端标记和凝胶电泳法。(3) 生殖细胞增殖调控基因的表达及其意义 细胞凋亡。基因表达将在测试前和测试期间进行分析 原位免疫细胞化学显示精子发生下降 杂交、原位聚合酶链式反应和Northern印迹分析。 这些研究将使我们更好地理解 精子发生和某些形式的男性不育；它们还可能 揭示男性避孕的潜在新目标。

Spermatogenesis is an androgen-dependent process and androgen-binding protein (ABP), a secretory product of Sertoli cells, is considered a mediator of androgens action on the developing germ cells. However, ABP's precise mode of action is not known. In order to understand the functions of ABP and, in a broader sense, the role of androgens in the control of spermatogenesis, we have studied transgenic mice expressing high amounts of ABP. These animals show progressive abnormalities of spermatogenesis and an eventual loss of fertility. In order to explain this finding, we hypothesize that the chronic overproduction of ABP changes the balance between proliferation and degeneration (apoptosis) of germ cells by changing the steroid hormone milieu within the seminiferous tubules. This may involve not only testosterone, but also is biologically active intratesticular metabolites dihydrotestosterone and estradiol. To test the above hypothesis, we propose to determine the effects of excess ABP produced in the transgenic animals on (1)-- testicular levels of testosterone, dihydrotestosterone, estradiol, and the androgen and estrogen receptors. Specific radioimmunoassays, immunocytochemistry, and in situ hybridization will be used to achieve this goal. (2)--the kinetics of germ cell proliferation and apoptosis preceding and during the decline in spermatogenesis. Flow cytometry and morphometric analysis will be used after specific labeling of both proliferating and apoptotic cells. Apoptosis will be detected by in situ end labeling of fragmented DNA and by gel electrophoresis. (3)-- the expression of genes regulating germ cell proliferation and apoptosis. Gene expression will be analyzed before and during the decline in spermatogenesis by immunocytochemistry, in situ hybridization, in situ PCR, and Northern blot analysis. These studies will lead to a better understanding of the regulation of spermatogenesis and of some forms of male infertility; they may also reveal potential new targets for male contraception.