[11-Dehydro-TXB2 and 2,3-dinor-TXB2 as new parameters of TXA2 generation]

Artifactual formation of thromboxane (TX) B2 during blood collection falsifies real value of TXB2 in plasma. A part (29.3%) of TXB2 is metabolized to 11-dehydro (DH)-TXB2 in several organs. 11-DH-TXB2 was not generated during blood collection or during serum formation. The peak amount of 11-DH-TXB2 after intravenous injection of TXB2 to rabbits was lower than that of TXB2, but the level of 11-DH-TXB2 was kept 2-3 times higher than that of TXB2 even after more than 5 min. A half life of 11-DH-TXB2 is 45-60 min in the human. Large species differences were found. In human urine, 11-DH-TXB2 was excreted 1.5-5.8 times more than 2,3-dinor-TXB2. Patients with ARDS and DIC, who received platelet transfusion, excreted increased amounts of 2,3-dinor-TXB2 and 11-DH-TXB2 in urine. 11-DH-TXB2 may be a useful parameter of TXA2 formation in pathological states.