Ong D E, Takase S, Chytil F
Departments of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Ann N Y Acad Sci. 1987;513:172-8. doi: 10.1111/j.1749-6632.1987.tb25007.x.
Vitamin A plays an important role in the testis, being essential for the maintenance of spermatogenesis. Studies on CRBP and CRABP suggest that both retinol and retinoic acid are involved in maintaining testicular function. The cellular location of the two proteins suggests that retinoic acid may be particularly involved in the later stages of germ cell differentiation, but retinol may be the form of vitamin A that the Sertoli cell receives initially. The requirement for vitamin A may be to regulate gene expression in the testis by direct interaction with the chromosomal material. Specific distinct binding sites for retinol and retinoic acid can be demonstrated in testicular nuclei and chromatin. These sites are only revealed when the two ligands are present in complex with their specific binding proteins, suggesting that these proteins may be required for the action of retinol and retinoic acid in some cells of the testis.
维生素A在睾丸中起着重要作用，对维持精子发生至关重要。对细胞视黄醇结合蛋白（CRBP）和细胞视黄酸结合蛋白（CRABP）的研究表明，视黄醇和视黄酸都参与维持睾丸功能。这两种蛋白质的细胞定位表明，视黄酸可能特别参与生殖细胞分化的后期阶段，但视黄醇可能是支持细胞最初接收的维生素A形式。对维生素A的需求可能是通过与染色体物质直接相互作用来调节睾丸中的基因表达。在睾丸细胞核和染色质中可以证明视黄醇和视黄酸有特定的不同结合位点。只有当这两种配体与其特异性结合蛋白形成复合物时，这些位点才会显现出来，这表明这些蛋白质可能是视黄醇和视黄酸在睾丸某些细胞中发挥作用所必需的。
