leukotriene-c-5 and Mast-Cell-Sarcoma

(10L)- and (10D)-[1-14C, 10-3H]5,8,11,14,17-eicosapentaenoic acids were synthesized to investigate mechanistic and stereochemical aspects of leukotriene biosynthesis. Experiments with mastocytoma cells showed that a hydrogen is stereospecifically eliminated from C-10 during the conversion of eicosapentaenoic acid to leukotriene C5. The hydrogen lost has the pro-S (D) configuration. 5-Hydroxy-6,8,11,14,17-eicosapentaenoic acid, formed in the same experiments, was enriched in tritium when the (10D), but not when the (10L), isomer of labeled eicosapentaenoic acid was used. This indicates that oxygenation of the acid at C-5 occurred before the elimination of hydrogen and suggests that removal of the pro-S hydrogen at C-10 in 5-hydroperoxy-6,8,11,14,17-eicosapentaenoic acid initiates its transformation to trans-5(S),6(S)-oxido-7,9-trans-11,14,17-cis-eicosapentaenoic acid (leukotriene A5).

Topics: Animals; Blood Platelets; Carbon Radioisotopes; Eicosapentaenoic Acid; Fatty Acids, Unsaturated; Humans; Mast-Cell Sarcoma; Mice; Sarcoma, Experimental; SRS-A; Tritium

14C-labeled eicosapentaenoic acid (n-3) was converted by mouse mastocytoma cells to 5-hydroxy-6-S-glutathionyl-7,9,11,14,17-eicosapentaenoic acid (leukotriene C5). The identification was based on comparisons with previously characterized unlabeled material by high-performance liquid chromatography, ultraviolet spectroscopy, and conversion by gamma-glutamyl transpeptidase to leukotriene D5.

Topics: Animals; Chromatography, High Pressure Liquid; Eicosapentaenoic Acid; Fatty Acids, Unsaturated; gamma-Glutamyltransferase; Mast-Cell Sarcoma; Mice; Sarcoma, Experimental; Spectrophotometry, Ultraviolet; SRS-A

Mouse mastocytoma cells incubated with ionophore A23187 and eicosapentaenoic acid (n-3) produced a slow reacting substance with different properties compared with leukotriene C4 (previously designated leukotriene C). This product was characterized by spectroscopy and enzymatic and chemical degradations to be 5-hydroxy-6-S-glutathionyl-7,9,11,14,17-eicosapentaenoic acid (leukotriene C5). Leukotriene C5 has similar biological activity on the isolated guinea pig ileum but is less potent than is leukotriene C4.

Topics: Animals; Biological Assay; Cell Line; Chromatography, High Pressure Liquid; Eicosanoic Acids; Eicosapentaenoic Acid; Fatty Acids, Unsaturated; gamma-Glutamyltransferase; Guinea Pigs; Ileum; Kidney; Lipoxygenase; Mast-Cell Sarcoma; Mice; Plants; SRS-A