Thromboxane formation from arachidonic acid and prostaglandin H2 in rabbit spleen

Incubation of [1-14C]arachidonic acid (AA) and [1-14C]prostaglandin (PG)H2 with rabbit spleen homogenate and microsomes resulted in the formation of a substance with the chromatographic properties of thromboxane (Tx)B2. The radiolabeled material was indistinguishable from authentic TxB2 on TLC in three solvent systems and on radiometric gas chromatography. The generation of TxB2-like material from AA and PGH2 was not observed after boiling of the homogenate and microsomes, and was completely inhibited by imidazole (5 mM). The transformation of AA into the TxB2-like material was not observed during incubation in the presence of indomethacin (28 microM). These results indicate that TxB2 is the principal product of arachidonic acid metabolism by the homogenate or microsomes of rabbit spleen.