Brooks D E
J Reprod Fertil. 1983 Jan;67(1):97-105. doi: 10.1530/jrf.0.0670097.
The incorporation of radioactive mannose and fucose into secretory glycoproteins by rat epididymal tissue was studied using tissue pieces in vitro. The appearance of radioactive macromolecular products in the medium occurred after a lag phase of 2 h with radioactive mannose, but with radioactive fucose the lag phase was only 15 min. Preincubation of tissue for 2 h before the addition of radioactive mannose increased the subsequent rate of incorporation by reducing the lag phase from 2 to 1 h. Tunicamycin reduced the incorporation of radioactive mannose and fucose into macromolecular products to approximately 15 and 50% of normal in the caput and cauda respectively; maximum inhibition required 10 micrograms tunicamycin/ml in the caput and 2 micrograms/ml in the cauda. Reduction of radioactive sugar incorporation by tunicamycin did not result in qualitative changes in the profile of the radioactive glycoproteins that were secreted. However, immunoprecipitation of proteins D and E from incubations with radioactive methionine or mannose revealed that tunicamycin caused these proteins to be synthesized and secreted in a non-glycosylated form. Prior castration of animals reduced the incorporation of radioactive mannose and fucose, and qualitative changes in the profiles of secreted radioactive glycoproteins were apparent.
利用体外组织块研究了大鼠附睾组织将放射性甘露糖和岩藻糖掺入分泌性糖蛋白的情况。培养基中放射性大分子产物的出现，在加入放射性甘露糖时经过2小时的延迟期，但加入放射性岩藻糖时延迟期仅15分钟。在加入放射性甘露糖之前将组织预孵育2小时，通过将延迟期从2小时缩短至1小时，提高了随后的掺入速率。衣霉素将放射性甘露糖和岩藻糖掺入大分子产物的量分别降至附睾头和附睾尾正常水平的约15%和50%；附睾头最大抑制所需衣霉素浓度为10微克/毫升，附睾尾为2微克/毫升。衣霉素减少放射性糖的掺入并未导致所分泌的放射性糖蛋白谱的定性变化。然而，从用放射性甲硫氨酸或甘露糖孵育的样品中对蛋白质D和E进行免疫沉淀显示，衣霉素使这些蛋白质以非糖基化形式合成和分泌。预先阉割动物会降低放射性甘露糖和岩藻糖的掺入，并且所分泌的放射性糖蛋白谱的定性变化很明显。
