MEASUREMENTS OF LEUKOTRIENES IN HUMAN PLASMA BY SOLID-PHASE EXTRACTION AND HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

Leukotrienes (LTs) are biologically active compounds derived from lipo xygenase catalyzed metabolism of arachidonic acid in mammalian tissues . The present report describes a simple method for extraction and isol ation of dihydroxy-LTs; LTB4, LTB5 and the peptido-LTs; LTC4, LTD4 and LTE4 from human plasma, using a pretreatment cartridge which utilizes both hydrophobic and ion-exchange interactions. 5 ml acidified plasma or acetate buffer containing commercially available LT standards were passed through the cartridges under suction, and the absorbed LTs wer e subsequently eluted in a stepwise manner with acetate buffer contain ing increasing amounts of methanol. The eluted LTs were analyzed by re versed-phase high performance liquid chromatography (HPLC) on octadecy lsilyl (ODS)-silica, using a Waters HPLC unit. Both with plasma and ac etate buffer the present methodology resulted in good separation of th e LTs with a total run-time of less than 32 min. Recovery of dihydroxy -LTs was approximately 80% (range 73-82%) both when the standards were dissolved in plasma and in acetate buffer. Recovery of the peptido-LT s was, however somewhat lower (47-50%). It should be noted that the pr esent method has the advantage that exposure to chemicals of high toxi city is avoided.