ABP AND THE REGULATION OF GERM CELL APOPTOSIS IN TESTIS

精子发生是一个雄激素依赖的过程， 支持细胞的分泌产物ABP被认为是 雄激素作用于发育中的生殖细胞的介质。 然而，在这方面， ABP的确切作用方式尚不清楚。 为了解 ABP的功能，以及更广泛意义上的雄激素在动脉粥样硬化中的作用 控制精子发生，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异常， 精子生成和最终丧失生育能力。 为了解释 根据这一发现，我们假设ABP的慢性过度产生 改变增殖和变性（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激素， 是生物活性睾丸内代谢物二氢睾酮 和雌二醇。 为了验证上述假设，我们建议确定 转基因动物中产生的过量ABP对（1）-- 睾丸睾酮、双氢睾酮、雌二醇水平， 雄激素和雌激素受体。 特异性放射免疫测定， 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 在精子发生下降之前和期间。 流式细胞术和 在特异性标记两者之后将使用形态计量分析。 增殖和凋亡细胞。 细胞凋亡将通过在 片段化DNA的原位末端标记和凝胶电泳。 （3）-- 调节生殖细胞增殖的基因的表达， 凋亡 基因表达将被分析之前和期间， 原位免疫细胞化学法测定精子生成减少 杂交、原位PCR和北方印迹分析。 这些研究将有助于更好地了解 精子发生和某些形式的男性不育;他们也可能 揭示了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.