The study of the arachidonoyl molecular species of alkylacyl glycerophosphocholine of rabbit alveolar macrophages

本课题的目的是利用一位首席研究员开发的高效液相色谱仪，了解磷脂分子物种，特别是花生四烯酰基分子物种和作为血小板激活因子前体的烷基酰基GPC的代谢特征。主要研究结果如下：1)兔肺泡巨噬细胞中的磷脂至少由130种不同的分子组成。总磷脂中的优势物种之一是16：0~20：4的烷基酰基GPC。在花生四烯酰基中，16：0-20：4的烷基酰基GPC的比例较高，为20：4(占总花生四烯酰基物种的20%)。2)考察了[&lt；^3H&gt；]20：4在单个物种中的掺入率。磷脂的结构性质对20：4的掺入有很大的影响。优势种16：0-20：4的烷基酰基GPC的比放射性明显低于其他分子种。3)经调理的酵母多糖刺激，肺泡巨噬细胞从磷脂中显著释放20：4。为了确定20：4的来源，考察了不同种类磷脂的相对降解率。16：0~20：4种烷基GPC释放的20：4量最大，约占磷脂释放总量20：4的50%，说明16：0~20：4种烷基GPC可能是肺泡巨噬细胞主要的细胞内储存物质，也是20：4的主要来源。

The purpose of this project is to know the feature of the metabolism of the molecular species of phospholipids, especially arachidonoyl molecular species and alkylacyl GPC which is a precursor of platelet activating factor, using high performance liquid chromatography which is developed by a head investigator. The main results are as following;1) Phospholipids in rabbit alveolar macrophages were composed of at least 130 different molecular species. One of the predominant species in the total phospholipids was the 16:0-20:4 species of alkylacyl GPC. In arachidonoyl species, a high proportion of 20:4 was associated with the 16:0-20:4 species of alkylacyl GPC (20% of the total arachidonoyl species).2) The rate of incorporation of [ <^3H> ]20:4 into individual species was investigated. The incorporation of 20:4 into phospholipids was greatly influenced by the nature of their structures. The specific radioactivity of the 16:0-20:4 species of alkylacyl GPC, which was a predominant species, was quite lower than other molecular species.3) Alveolar macrophages significantly released 20:4 from phospholipids by the stimulation of the opsonized zymosan. To determine the source of 20:4, the relative degradation of individual species of phospholipids was examined. The amounts of 20:4 liberated from the 16:0-20:4 species of alkylacyl GPC was greatest, representing almost 50% of the total 20:4 released from phospholipids.These resuts indicate that the 16:0-20:4 species of alkylacyl GPC may play an important role as a major intracellular storage and also source of 20:4 in alveolar macrophages.