tetranor-PGEM is the major urinary metabolite of PGE1 and PGE2, and is used as a marker of PGE2 biosynthesis.[1],[2] About 15% of an infused dose of PGE2 appears as this metabolite in the urine of humans. Normal healthy males excrete 7-40 µg of tetranor-PGEM over a 24-hour period.[1]
Reference:
[1]. Hamberg, M. Inhibition of prostaglandin synthesis in man. Biochemical and Biophysical Research Communications 49, 720-726 (1972).
[2]. Honda, H., Fukawa, K., and Sawabe, T. Influence of adjuvant arthritis on main urinary metabolites of prostaglandin F and E rats. Prostaglandins 19, 259-269 (1980).