Structure of the major urinary metabolite of prostaglandin E2 in man

This letter reports the structure of the major urinary metabolite formed from prostaglandin E2 (PGE2) in humans. Radiolabeled PGE2 was injected intravenously into male subjects. 50% of the radioactivity was recovered in urine during the first 5 hours and less than 3% during the following 12 hours. The urine was acidified, and this extract was subjected to reversed-phase partition chromatography. Formation of the major metabolite (depicted stereochemically in the text) from PGE2 involved 4 steps of reactions: 1) dehydrogenation of the alcohol group in the side chain; 2) reduction of the trans double bond; 3) 2 steps of beta oxidation; and 4) delta oxidation.