METABOLISM OF 8 EPI PGF2 IN HEALTHY VOLUNTEERS

在过去的十年中，各种各样的病理状况都与氧化应激有关，这一领域的研究也得到了极大的发展。然而，氧化应激在人类疾病发病机制中的作用仍不清楚，这主要是由于目前评估体内氧化应激的方法的局限性。Morrow等人发现了一系列类似前列腺素的化合物，这些化合物是由非酶自由基催化花生四烯酸过氧化作用产生的。这些异前列腺素是由花生四烯酸酯化成磷脂在原位形成的，一旦以自由形式释放，就具有生物活性。异前列腺素似乎是体内氧化损伤的可靠标志物。然而，花生四烯酸的自氧化可能导致血浆中异前列腺素的人为增加，在更有限的程度上，也会导致尿液中异前列腺素的增加。尿中异前列腺素酶代谢产物的测定将克服这一问题，并提供一种可靠的、非侵入性的、综合的体内氧化应激指标。异前列腺素8-epi-PGF（2a）的主要尿代谢产物最近被确定为2,3-二-5,6-二氢-8-epi PGF（2a）。我们现在开发了气相色谱/负离子化学电离-质谱（GC/NICI-MS）技术，使我们能够特异性地定量尿中8-epi PGF的排泄（2a）。我们现在提议评估5名健康志愿者在输注增加剂量的8-epi PGF（2a）后这些化合物的尿排泄。此外，我们还拥有电喷雾质谱和技术专长，可以尝试鉴定输注的8-epi-PGF的极性代谢物（2a）。

Over the past ten years a wide variety of pathological conditions has been linked to oxidative stress and research in this field has undergone a tremendous growth. However, the role played by oxidative stress in the pathogenesis of human diseases is still unclear mainly due to limitation of current methodology to assess oxidant stress in vivo. Morrow et al. have discovered a series of prostaglandin-like compounds that are produced by nonenzymatic free radical catalyzed peroxidation of arachidonic acid. These isoprostanes are formed in situ from arachidonic acid esterified to phospholipids and, once released in free form, are capable of biological activity. The isoprostanes appear to be reliable markers of oxidant injury in vivo. However, auto-oxidation of arachidonic acid may lead to artifactual increase of isoprostanes in plasma and, to a more limited degree, in urine. The measurement of urinary enzymatic metabolites of the isoprostanes would overcome this problem and would provide a reliable, non-invasive and integrated index of oxidant stress in vivo. The major urinary metabolite of the isoprostane 8-epi-PGF(2a) has been recently identified as the 2,3-dinor-5,6-dihydro-8-epi PGF(2a). We have now developed gas chromatography/negative ion chemical ionization-mass spectrometry (GC/NICI-MS) techniques that enable us to quantiate specifically the urinary excretion of both 8-epi PGF(2a). We now propose to assess the urinary excretion of these compounds following infusion of increasing doses of 8-epi PGF(2a) in five healthy volunteers. In addition, we have an electrospray mass spectrometry and the technical expertise to attempt the identification of polar metabolites of infused 8-epi-PGF(2a).