Enzymatic formation of hepoxilins A3 and B3.

Available data obtained so far has indicated that hepoxilin formation from 12-HPETE is catalyzed by hemin and hemoglobin and is not affected through heating of these ferri-heme compounds suggestive of nonenzymatic processes. The present paper demonstrates for the first time that 12-HPETE is transformed into the hepoxilins A3 and B3 by intact cells (skin subcutis layer) and slices of several tissues (brain hippocampus and pineal gland) and that this transformation is inhibited by tissue boiling, indicating an enzymatic catalysis. The tissues employed are pharmacologically responsive to hepoxilins and hence the present data offer biochemical support of a potential biological role for the hepoxilins in these tissues.