Monsees T K, Görnig M, Schill W B, Miska W
Center of Dermatology and Andrology, Justus Liebig University, Giessen, Germany.
Andrologia. 1998 Aug-Sep;30(4-5):185-91. doi: 10.1111/j.1439-0272.1998.tb01160.x.
Proteolytic enzymes, which are synthesized and secreted by cells of the seminiferous tubule of the testis, have important functions in spermatogenesis. We performed metabolic studies using small peptide hormones as a substrate to investigate the activity of proteases in cultured Sertoli cells of the rat. High-performance liquid chromatographic analysis of the cell culture supernatants showed cleavage of met- and leu-enkephalin, substance P, and bradykinin. No peptidolysis was observed for the cyclic peptide oxytocin. The hormone cleavage pattern and the use of specific protease inhibitors in peptide degradation experiments demonstrated activities of several proteases in Sertoli cells. These are mainly metalloproteinases including neutral metalloendopeptidases, angiotensin-converting enzyme and aminopeptidases. In addition, activities of serine and aspartic proteases were detected. Only marginal proteolytic activities were observed in Sertoli cell conditioned supernatants, indicating that the investigated proteases are mainly located on Sertoli cell membranes. The peptide hormones used in this study have been found to play a potential role in the endocrine, paracrine or autocrine regulation of testicular cells. The membrane-associated proteases reported here may therefore be involved in the metabolism and inactivation of these peptides.
蛋白水解酶由睾丸生精小管细胞合成并分泌，在精子发生过程中具有重要作用。我们以小肽激素为底物进行代谢研究，以探究大鼠培养支持细胞中蛋白酶的活性。对细胞培养上清液进行高效液相色谱分析，结果显示甲硫氨酸脑啡肽、亮氨酸脑啡肽、P物质和缓激肽均有裂解。而环肽催产素未观察到肽水解现象。激素裂解模式以及在肽降解实验中使用特异性蛋白酶抑制剂，证实了支持细胞中几种蛋白酶的活性。这些蛋白酶主要是金属蛋白酶，包括中性金属内肽酶、血管紧张素转换酶和氨肽酶。此外，还检测到了丝氨酸蛋白酶和天冬氨酸蛋白酶的活性。在支持细胞条件培养基上清液中仅观察到少量蛋白水解活性，这表明所研究的蛋白酶主要位于支持细胞膜上。本研究中使用的肽激素已被发现可能在睾丸细胞的内分泌、旁分泌或自分泌调节中发挥作用。因此，本文报道的膜相关蛋白酶可能参与这些肽的代谢和失活过程。
