Mobilization of different arachidonate pools and their roles in the generation of leukotrienes and free arachidonic acid during immunologic activation of mast cells.

摘要: Immunologic activation of mast cells leads to the mobilization arachidonic acid (AA) from membrane phospholipids and subsequent conversion this AA bioactive products. The objective our study was determine if segregated pools AA-containing within serve as independent sources AA. Initial studies indicated that appearance free occurred rapidly (maximal level formed 1 min) supernatant fluids Ag-stimulated kinetically different formation leukotriene (LT) B4 or LTC4. To examine whether leukotrienes were mobilized sources, labeled with [14C] [3H] such all major subclasses (1-acyl-1-alkyl-1-alk-1'-enyl) contained ratios (sp. act. (SAR)). Mast then stimulated Ag SAR cellular AA, extracellular LTC4, LTB4, 6-trans determined. uniform in LT mimicked ratio found By contrast, released into twofold lower than LT. This fatty clearly derived a lipid pool Although it apparent which gave rise different, defining phospholipid(s) constitute these distinct proved more difficult. suggested their precursor could have been several phospholipid subclasses; however, phosphatidylcholine phosphatidylinositol most closely matched implied derived, part, phosphatidylethanolamine subclasses. Taken together, data suggest there are at least two during activation.