Turnbull L S, Jones D G, Kay A B
Immunology. 1976 Nov;31(5):813-20.
Homogenates from human lung contained a preformed slow reacting substance (pSRS). The pattern of contraction on the guinea-pig ileum by pSRS was indistinguishable from that of SRS-A. The activity of pSRS could not be attributed to the presence of K+, Na+, Ca2+ and Mg2+ ions, or any prostaglandin including PGF2 or its 15-oxo derivative. As with SRS-A, pSRS could be absorbed onto Amberlite XAD-2 and silicic acid. Both were eluted from the former with 80 per cent ethanol and from the latter with a mixture of ethanol, ammonia and water. Both pSRS and SRS-A were resistant to the action of NaOH whereas their activities were destroyed by boiling in HCl. Arylsulphatase II B destroyed the activities of both pSRS and SRS-A. An antagonist of SRS-A, FPL55712, inhibited the action of pSRS at comparable concentrations to that of SRS-A. These experiments suggest that pSRS and SRS-A are identical. Thus SRS joins histamine and ECF-A as a preformed mediator. Although SRS was present in a preformed state the amount of material extractable was more than doubled by the anaphylactic reaction. The extraction of slow reacting substance from human lung without apparent requirement for antigen or antibody points to a possible role of this mediator in inflammatory reactions evoked by mechanisms independent of IgE and other tissue-sensitizing antibodies.
人肺匀浆中含有一种预先形成的慢反应物质（pSRS）。pSRS对豚鼠回肠的收缩模式与SRS-A的收缩模式无法区分。pSRS的活性不能归因于K⁺、Na⁺、Ca²⁺和Mg²⁺离子的存在，也不能归因于任何前列腺素，包括PGF₂或其15-氧代衍生物。与SRS-A一样，pSRS可被吸附到Amberlite XAD-2和硅酸上。两者都用80%乙醇从前者洗脱，用乙醇、氨和水的混合物从后者洗脱。pSRS和SRS-A都对NaOH的作用有抗性，而它们的活性在HCl中煮沸会被破坏。芳基硫酸酯酶II B会破坏pSRS和SRS-A的活性。SRS-A的拮抗剂FPL55712在与SRS-A相当的浓度下抑制pSRS的作用。这些实验表明pSRS和SRS-A是相同的。因此，SRS作为一种预先形成的介质，加入了组胺和ECF-A的行列。尽管SRS以预先形成的状态存在，但过敏反应使可提取的物质数量增加了一倍多。从人肺中提取慢反应物质，显然不需要抗原或抗体，这表明这种介质在由独立于IgE和其他组织致敏抗体的机制引发的炎症反应中可能发挥作用。
