Biological role of kininogens; Studies using kininogen deficient rats.

1.大鼠高、低分子质量的放射免疫分析(RIA)(LMW)-激肽原和T-激肽原分别用这些激肽原的特异性单抗或多克隆抗体制备。通过测定发现，B/N-Katholiek品系大鼠血浆HMW-和LMW-激肽原水平是正常大鼠(B/N-Kitasato品系)的3%，而原肝中HMW-和LMW-激肽原水平约为正常大鼠的60%。结果：1.肝细胞原代培养实验表明，B/N-Katholiek大鼠肝脏可合成激肽原，但不能将激肽原分泌到培养液中，提示大鼠存在分泌缺陷。免疫印迹分析发现，在角叉菜胶诱导的胸膜炎渗出液中，HMW-激肽原是一种无激动素的蛋白。结果提示，HMW-激肽原可能通过释放激肽诱导血浆渗出。此外，当用卡托普利预处理大鼠时，缺陷品系中渗出液中的花生四烯酸代谢产物明显少于正常品系。这一结果还表明，存在一条通过激活激动素系统释放二十烷类化合物的途径。从而证明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，炎症后两个品系大鼠血浆中T-激肽原水平均升高。角叉菜胶致炎后2~3d，血浆浓度升高10~20倍。而T激肽原水平升高的大鼠在炎症反应方面与对照组无明显差异，说明T激肽原既不是促炎剂，也不是抗炎剂。雌性大鼠的T-激肽原水平高于雄性大鼠，雌激素治疗使幼年大鼠的T-激肽原水平升高。结果提示，T-激肽原的生物合成存在激素调节。

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.