Cyclooxygenase and lipoxygenase metabolites during platelet aggregation: quantitative measurement by negative ion chemical ionization--gas chromatography/mass spectrometry.

This study was aimed at investigating systematically the aggregation of human gel filtered platelets induced by various physiological stimuli such as thrombin (0.25 U/ml), collagen (2 micrograms/ml), a mixture of thrombin and collagen, and ADP (2-5 microM). For quantitative measurement of TXB2, PGF2 alpha and 12-HETE, negative ion chemical ionization-gas chromatography/mass spectrometry using stable isotope dilution was applied. Stimulation by thrombin, collagen and the combined agonists resulted in an increase of TXB2 (up to 54 ng/1 X 10(8) platelets) and 12-HETE (up to 44 ng/1 X 10(8) platelets) during platelet aggregation. The stimulation with ADP showed only little increase of these metabolites and this only during the second wave of aggregation. Very little amounts of PGF2 alpha were produced during thrombin stimulated aggregation.