1a,1b-dihomo Prostaglandin E2 (PGE2) is a rare polyunsaturated fatty acid first identified in extracts of sheep vesicular gland microsomes, known to contain COX, incubated with adrenic acid . 1a,1b-dihomo PGE2 has also been identified in conditioned media of RAW 264.7 macrophages stimulated with endotoxin and arachidonic acid (AA; ). This product is thought to be produced by elongation of AA to adrenic acid, which is then metabolized sequentially by COX and PGE synthase.
