Evidence for an extra-renal origin of urinary prostaglandin E 2 in healthy men

Abstract

In order to verify the validity of the assumption that male urinary Prostaglandin (PG) E 2 reflects its renal production, PGE 2 and PGF 2α concentrations were measured by radioimmunoassay in the renal venous plasma (RVP) and urine (U) of 12 male and 4 female healthy volunteers. While women had a similar PGE 2/PGF 2α ratio in RVP (0.59 ± 0.18) and U (0.41 ± 0.06), men had a significantly ( p < 0.05 ) higher ratio in U (1.43 ± 1.72) as compared to RVP (0.54 ± 0.16). This was largely due to considerably higher and more variable U-PGE 2 concentrations (roughly 6 times higher than female values), despite almost identical RVP levels. The possibility of an increased U excretion of a cross-reacting member of the PG-system, as a cuase of such apparently high PGE 2-like immunoreactivity (LI), was ruled out by TLC characterization of PGE 2-LI with three different anti-PGE 2 sera. Thus, male U-PGE 2 may variably reflect an extra-renal source, such as contamination with trace amounts of seminal fluid. It is concluded that, unless such a contamination can be monitored and corrected for, measurement of male U-PGE 2 should be considered of questionable relevance to renal PG-synthesis.