The purpose of this study was to clarify whether human amniotic fluid (AF) contains a significant level of bioactive lysophosphatidic acid (LPA) and, whether autotaxin (ATX) is involved in the production of LPA, if present. Using LC–MS/MS, we found a higher ratio of levels of LPA and its precursor lysophosphatidylcholine (LPC) in AF collected after parturition than that in AF collected at the middle stage of pregnancy. We detected significant choline-producing enzymatic activity toward an exogenous LPC in AF at the middle stage of pregnancy, about half of which was ascribable to ATX. In AF collected after parturition, the ATX-independent choline-producing activity of glycerophosphcholine phosphodiesterase coupled to lysophospholipase A activity was increased in relative to the lysophospholipase D activity of ATX. These results suggest that the increased LPA/LPC ratio in AF at the term of pregnancy was due to not only a moderate increase in the level of LPC, but also an unknown mechanism involving epithelial cells bathed with AF.

本研究的目的是阐明人羊水 (AF) 是否含有大量生物活性溶血磷脂酸 (LPA)，以及自分泌运动因子 (ATX) 是否参与 LPA 的产生（如果存在）。使用 LC-MS/MS，我们发现在分娩后采集的 AF 中 LPA 及其前体溶血磷脂酰胆碱 (LPC) 的水平比在妊娠中期采集的 AF 中更高。我们检测到妊娠中期 AF 中外源性 LPC 产生显着的胆碱酶活性，其中约一半归因于 ATX。在分娩后收集的 AF 中，与 ATX 的溶血磷脂酶 D 活性相比，与溶血磷脂酶 A 活性偶联的甘油磷酸胆碱磷酸二酯酶的 ATX 非依赖性胆碱产生活性增加。