Biological role of kininogens; Studies using kininogen deficient rats.

1.大鼠高分子量（HMW）、低分子量的放射免疫测定（RIA）。分别使用这些激肽原的特异性单克隆或多克隆抗体开发了（LMW）-激肽原和T-激肽原。通过这些测定，我们发现B/N-Katholiek品系大鼠的血浆HMW-和LMW-激肽原水平是正常大鼠（B/N-Kitasato品系）的3%，而前者肝脏中的水平约为正常大鼠的60%。肝细胞原代培养实验表明，B/N-Katholiek大鼠肝脏合成激肽原，但不能分泌到培养液中，说明该大鼠存在分泌缺陷.在角叉菜胶诱导的胸膜炎渗出液中，通过免疫印迹分析发现HMW-激肽原是一种不含激肽的蛋白质。结果提示，高分子量激肽原可能通过释放激肽而引起血浆渗出。此外，花生四烯酸代谢产物在渗出液中的缺陷株显着低于正常株，当大鼠与卡托普利预处理。这一结果还表明，存在通过激活激肽系统释放类花生酸的途径。从而证明了激肽系统在炎症反应中的重要作用.大鼠T-激肽原是一种独特的激肽原，其在两种品系大鼠血浆中的水平在炎症后均升高。在角叉菜胶炎症后2-3天，血浆水平增加10 - 20倍。然而，具有增加的T-激肽原水平的大鼠在炎症反应中与对照大鼠没有显示出任何差异，表明T-激肽原不是促炎剂或抗炎剂。雌性大鼠的T-激肽原水平高于雄性大鼠，雌激素治疗可增加幼鼠的T-激肽原水平。结果提示，T-激肽原的生物合成受激素调节。

1. Radioimmunoassays (RIA) of rat high molecular weight (HMW)-, low molecular, weight. (LMW)-kininogen and T-kininogen were developed using specific monoclonal or polyclonal antibodies to these kininogens respectively. By these assays we found that-plasma levels of HMW- and LMW- kininogens of B/N-Katholiek strain rats were 3% of the normal rats (B/N- -Kitasato strain), whereas the levels in the former liver were about 60 % of those of the normal rats. Experiment with hepatocyte primary culture showed that the liver of B/N-Katholiek synthesized the kininogens but could not secrete them into the medium, indicating that the rat has a secretion defect.2. In the exudate of carrageenin induced pleurisy HMW-kininogen was found to be a form of kinin-free protein by immunoblot analysis. The result suggests that kinin may be released from HMW-kininogen to induce plasma exudation. Furthermore arachidonate metabolites in the exudate was significantly less in the deficient strain in comparison with those in the normal strain, when rats were pretreated with captopril. The result also indicates that there is a pathway of release of eicosanoids through the activation of the kinin system. Thus it proves an important role of the kinin system in inflammation.3. Rat T-kininogen is a unique kininogen and its level in rat plasma of both strains increased after the inflammation. The plasma level increased 10 - 20 fold at 2-3 days after the carrageenin inflammation. However the rats had increased level of T-kininogen did not show any difference in inflammatory reaction from control rats, indicating that T-kininogen is not pro- or anti-inflammatory -agent. T-kininogen level in female rats was higher than that in male rats and a treatment with estrogen increased T- kininogen level in young rats. The result suggests that there is.a hormonal regulation of biosynthesis of T-kininogen.