In vivo formation of leukotriene E5 by murine peritoneal cells.

Resident mouse peritoneal cells, stimulated in vivo with opsonized zymosan, produced leukotriene C4 and E4, with LTE4 being the major (80-90%) product. When mice were placed on diets containing increasing amounts of fish oil, four additional sulfidopeptide leukotrienes (SP-LT), LTC5, LTE5, 11-trans LTC5 and 11-trans LTE5, were identified. The identity of LTE5 was confirmed by spectrophotometric, chromatographic and enzymatic methods. When equivalent amounts of n-6 and n-3 polyunsaturated fatty acids (PUFA) were included in the diet, the stimulated peritoneal cells (in vivo) produced higher quantities of LTE5 (30.2 +/- 5.4 ng/10(6) cells) than LTE4 (22.8 +/- 7.3 ng/10(6) cells). In addition, in vitro studies demonstrated a 60% reduction in LTC4 (42.0 +/- 10.8 ng/10(6) cells to 16.7 +/- 6.2 ng/10(6) cells) and the appearance of LTC5 (2.1 +/- 0.9 ng/10(6) cells) in resident macrophages (stimulated with A23187) from mice maintained on a fish oil diet compared to mice fed the control diet. This study demonstrated that formation of the pentaenyl SP-LT in vivo, in particular LTE5, by peritoneal cells can significantly contribute to the endogenous SP-LT pool in response to an inflammatory stimulus following a dietary regimen containing fish oil.