Formation of Leukotrienes E3, E4,E5 in Rat Basophilic Leukemia Cells

Abstract
Rat basophilic leukemia (RBL-1) cells incubated with ionophore A23187 [calcimycin] and 5,8,11-eicosatrienoic acid produced 3 slow-reacting substances identified as leukotrienes C3, D3 and E3 by spectroscopic, chromatographic and enzymatic methods. 5,8,11,14,17-Eicosapentaenoic acid was similarly converted by RBL-1 cells to leukotrienes C5, D5 and E5. Leukotrienes C4, D4 and E4 were also formed in these experiments from endogenous arachidonic acid. Time-course studies, incubations with 3H-labeled leukotriene C3 and effects of acivicin [L-(.alpha.S,5S)-.alpha.-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid; a .gamma.-glutamyl transpeptidase inhibitor] indicated that leukotrienes C and D are intermediates in the formation of leukotrienes E. L-Cysteine enhanced the conversion of leukotriene C3 to leukotriene D3 and inhibited further degradation of leukotriene D3 to leukotriene E3.