Measurement of prostaglandin D2 and identification of metabolites in human plasma during intravenous fusion

A stable isotope dilution assay has been developed for the quantification of prostaglandin D₂4 (PGD₂) in plasma. Samples are analysed by capillary column gas chromatography/ negative ion chemical ionisation mass spectrometry (GC/NICIMS). The methods employs an internal standard of ²H₆]PGD₂, prepared biosynthetically by incubation of rat peritoneal mast cells with deuterated arachidonic acid.No PGD₂ was detected in peripheral venous plasma samples obtained from 10 healthy male volunteers (detection limit = 5 pg ml^?1). Following intravenous infusion of PGD₂ at increasing incremental infusion rates ranging from 16–256 ng kg^?1 min^?1, a dose related increase in the plasma concentration of PGD₂ was observed. Plasma levels at 128 ng kg^?1 min^?1 ranged from 724–1444 pg ml^?1. The major circulating metabolites of PGD₂, during infusion, were identified as 13,14-dihydro-15-oxo-PGF_2α and 15-oxo-PGF_2α.