[6] Quantification of 9α,11β-prostaglandin F2 by stable isotope dilution mass spectrometric assay

Publisher Summary The chapter presents a study on quantification of 9 α , 11 β -prostaglandin F 2 (9 α , 11 β -PGF 2 ) by stable isotope dilution mass spectrometric assay. 9α, 11β -PGF 2 has been found to be biologically active. Transformation of an eicosanoid formed directly from PGH 2 to a biologically active metabolite is unique to PGD 2 . 9α, 11β -PGF 2 has been found to contract human bronchial smooth muscle, contract coronary arteries, inhibit platelet aggregation, induce natruresis, and it is a pressor substance. The chapter offers information on developing a stable isotope dilution mass spectrometric assay for quantification of 9α, 11β -PGF 2 in biological fluids. This chapter details the preparation of the deuterium-labeled 9α, 11β -PGF 2 internal standard, the procedures employed for purification of 9α, 11β -PGF 2 in biological fluids, and the analysis of 9α, 11β -PGF 2 by gas chromatography-mass spectrometry (GC-MS). Specific examples are given demonstrating both the utility and the limitations of the assay. The chapter concludes by stating that the mass spectrometric assay that is developed provides a sensitive and accurate means for the analysis of 9α, 11β -PGF 2 in a variety of biological fluids. However, special precautions must be taken to differentiate 9α, 11β -PGF 2 from PGF 2 compounds present in biological fluids that arise from noncyclooxygenase oxidation of arachidonic acid rather than from 11-ketoreductase metabolism of PGD 2 .