Monsees T K, Miska W, Schill W B
Department of Dermatology and Andrology, Justus Liebig University, Giessen, Germany.
J Androl. 1996 Jul-Aug;17(4):375-81.
Sertoli cells play a key role in spermatogenesis. To study the involvement of the kallikrein-kinin system in the testis, the pattern of bradykinin-inactivating kininases in rat Sertoli cells was investigated. Exogenous bradykinin (Arg1-Pro2-Pro3-Gly4-Phe5-Ser6-Pro7-Phe8-Arg9) is cleaved at Pro7-Phe8, Phe5-Ser6, and Gly4-Phe5, as demonstrated by high performance liquid chromatography analysis. Degradation of bradykinin was strongly inhibited by phosphoramidon and thiorphan, which are specific inhibitors of neutral metalloendopeptidase-24.11. The kininase type II-specific inhibitors, captopril and enalapril, were only partially effective in preventing peptidolysis. This indicates that the main kininases responsible for rapid bradykinin inactivation are neutral metalloendopeptidase and, to a lesser extent, kininase type II. Neutral metalloendopeptidase and kininase type II were shown to be located on Sertoli cell membranes. A low degree of bradykinin degradation was detected by simultaneous inhibition of neutral metalloendopeptidase-24.11 and kininase II, pointing out the involvement of further peptidases with minor activities. This remaining activity is probably not due to the action of kininase type I or cysteine proteases, as shown by specific inhibitors. The data presented indicate the occurrence of membrane-bound kininases, which are an important part of the kallikrein-kinin system, in rat Sertoli cell cultures.
支持细胞在精子发生过程中起关键作用。为研究激肽释放酶-激肽系统在睾丸中的作用，对大鼠支持细胞中缓激肽失活激肽酶的模式进行了研究。高效液相色谱分析表明，外源性缓激肽（Arg1-Pro2-Pro3-Gly4-Phe5-Ser6-Pro7-Phe8-Arg9）在Pro7-Phe8、Phe5-Ser6和Gly4-Phe5处被裂解。缓激肽的降解受到磷酰胺和硫氧还蛋白的强烈抑制，这两种物质是中性金属内肽酶-24.11的特异性抑制剂。激肽酶II特异性抑制剂卡托普利和依那普利在防止肽水解方面仅部分有效。这表明负责快速使缓激肽失活的主要激肽酶是中性金属内肽酶，其次是激肽酶II。中性金属内肽酶和激肽酶II位于支持细胞膜上。通过同时抑制中性金属内肽酶-24.11和激肽酶II，检测到低程度的缓激肽降解，这表明存在其他活性较低的肽酶。如特异性抑制剂所示，这种剩余活性可能不是由于激肽酶I或半胱氨酸蛋白酶的作用。所提供的数据表明，在大鼠支持细胞培养物中存在膜结合激肽酶，它们是激肽释放酶-激肽系统的重要组成部分。
