VITAMIN A AND REPRODUCTION

这项建议的广泛的长期目标是了解基本的 维生素A在男性生殖功能中的作用， 了解必要的运动和维生素A的代谢， 睾丸和附睾。具体研究建议旨在澄清 维生素A的几种特异性转运或结合蛋白的作用 在这些器官中。特别强调了两个以前 未描述的维甲酸结合蛋白存在于附睾， 老鼠建议对这些蛋白质进行纯化和表征 包括测定序列、结合特异性和内源性 配体。蛋白质的分布和细胞定位将是 通过制备抗血清测定， 放射免疫分析和免疫定位。其他物种将被检查 这些蛋白质的存在。蛋白质的功能将是 通过研究它们将视黄酸递送到发育中的 精子 初步研究表明，原代培养的支持细胞 从其与视黄醇结合蛋白的复合物中内化视黄醇， 维生素A的血浆转运蛋白，以受体介导的方式。 这一过程将得到进一步的描述。的新陈代谢 将测定内化的视黄醇，特别强调 酯化和可能涉及新的酶活性， 卵磷脂视黄醇酰基转移酶塞尔托利可能会释放 将检查内化的维生素A的细胞向培养基的转化。的 将在无细胞系统中研究RBP的质膜受体， 在视黄醇从RBP转移到CRBP之后。纯化 将尝试RBP受体，以产生可用于 放射免疫分析和免疫定位。 最后，细胞视黄醇结合蛋白的细胞特异性定位 和细胞维甲酸结合蛋白 将被确定。用抗人CRBP的抗血清， 人类睾丸和附睾将继续进行。这些研究将 CRBP分布广泛，可延伸至卵巢和子宫。人CRABP 将被纯化，并获得抗CRABP的抗血清，用于 放射免疫测定和免疫定位研究类似于 CRBP。

The broad long-term goal of this proposal is to understand the essential role that vitamin A plays in male reproductive function, seeking to understand the necessary movements and metabolism of vitamin A in the testis and epididymis. The specific research proposed seeks to clarify the roles of several specific transport or binding proteins for vitamin A in these organs. Particular emphasis is given to two previously undescribed retinoic acid-binding proteins present in the epididymis of the rat. It is proposed to purify and characterize these proteins including determination of sequence, binding specificity, and endogenous ligand. The distribution and cellular location of the proteins will be determined by preparation of antiserum that can be used for sensitive radioimmunoassay and immunolocalization. Other species will be examined for the presence of these proteins., The function of the proteins will be examined by studying their ability to deliver retinoic acid to developing sperm. Preliminary work has shown that Sertoli cells in primary culture will internalize retinol from its complex with retinol-binding protein, the plasma transport protein for vitamin A, in a receptor-mediated fashion. This process will be further characterized. The metabolism of the internalized retinol will be determined, with particular emphasis on esterification and the possible involvement of a novel enzyme activity, lecithinretinol acyl transferase. The possible release by the Sertoli cell of the internalized vitamin A to the medium will be examined. The plasma membrane receptor for RBP will be studied in cell-free systems, following the transfer of retinol from RBP to CRBP. Purification of the RBP receptor will be attempted in order to produce antiserum usable for radioimmunoassay and immunolocalization. Finally, the cell-specific location of cellular retinol-binding protein and cellular retinoic acid-binding protein in human reproductive tissue will be determined. With antiserum to human CRBP, localization studies in human testis and epididymis will be continued. Such studies will be extended to ovary and uterus, two tissues with abundant CRBP. Human CRABP will be purified and antiserum to CRABP obtained that will be used for radioimmunoassay and immunolocalization studies similar to those for CRBP.