Effects of platelet stimulation on the metabolism of 5-HETE, 5S,12S-diHETE, and 5-oxo-ETE. Platelets (2 × 108) were incubated with either 5-HETE (2 μmol/L; 5h), 5S,12S-diHETE (2 μmol/L; 5,12-dh), or 5-oxo-ETE (2 μmol/L; 5o) for 10 minutes at 37°C in the absence (□) or presence of A23187 (5 μmol/L; ▪) or thrombin (1 U/mL; ▨). The products were quantitated by precolumn extraction/RP-HPLC as described in Materials and Methods. The four groups of bars (from left to right) show: (1) the amounts of 5-hydroxyeicosanoid dehydrogenase (dh) products (5-oxo-ETE + 5-oxo-12-HETE + 8-trans-5-oxo-12-HETE) formed from 5-HETE, (2) the amounts of dehydrogenase products (5-oxo-12-HETE + 8-trans-5-oxo-12-HETE) formed from 5S,12S-diHETE, (3) the amounts of 5-ketoreductase (kr) products (5-HETE + 5S,12S-diHETE) formed from 5-oxo-ETE, and (4) the amounts of 12-LO products (5-oxo-12-HETE + 8-trans-5-oxo-12-HETE + 5S,12S-diHETE) formed from 5-oxo-ETE. The values are means ± SE of determinations on platelets from four different donors.
