PHENYL RADICAL FORMATION BY OXYHEMOGLOBIN FROM PHENYLHYDRAZINE IN VIVO

氧合血红蛋白与苯肼的反应已收到 几十年来备受关注。 其基础 兴趣源于苯肼和肼的能力- 导致溶血性贫血的药物。 相当多的证据 从体外电子自旋共振（ESR）实验中获得 表明自由基参与了导致红细胞 溶血 然而，直到本报告，没有确证的ESR 已经提出了体内自由基形成的证据。 我们已经成功地利用电子自旋共振（ESR）检测到一种 自由基加合物在血液中的大鼠接受了胃内 剂量的苯肼，然后腹腔内注射 5-二甲基-1-吡咯啉N-氧化物（DMPO）的自旋陷阱。 的 用巯基试剂和C- 13-标记的苯肼使我们将DMPO自由基 加合物，以捕获血红蛋白衍生的巯基自由基。 除了苯肼之外，肼类药物异烟肼， 检查了异丙肼、苯乙肼和肼苯哒嗪。 四 药物，只有苯乙肼和异丙肼能够诱导 体内DMPO/血红蛋白巯基自由基加合物的形成， 而苯乙肼和肼苯哒嗪能够形成这种 体外加合物。 我们能够减少体内的异丙肼- 诱导加合物的形成，通过预处理大鼠与双-对- 磷酸硝基苯酯，一种芳基酰胺酶抑制剂。 我们的结果 支持这样的观点，即异丙肼在肝脏中水解为 反应性更强的代谢物，很可能是异丙基肼， 随后释放到血流中。

The reaction of oxyhemoglobin with phenylhydrazine has received considerable attention for many decades. The basis for this interest stems from the ability of phenylhydrazine and hydrazine- based drugs to induce hemolytic anemia. Considerable evidence obtained from in vitro electron spin resonance (ESR) experiments implicates free radicals in the events leading to red blood cell hemolysis. However, until this report, no corroborating ESR evidence for in vivo free radical formation has been presented. We have successfully employed ESR to detect the formation of a radical adduct in the blood of rats which received an intragastric dose of phenylhydrazine followed by an intraperitoneal injection of the spin trap 5-5-dimethyl-I-pyrroline N-oxide (DMPO). The results of a series of experiments with sulfhydryl reagents and C- 13-labelled phenylhydrazine led us to assign this DMPO radical adduct to the trapping of a hemoglobin-derived thiyl free radical. In addition to phenylhydrazine the hydrazine-based drugs isoniazid, iproniazid, phenelzine, and hydralazine were examined. Of the four drugs, only phenelzine and iproniazid were able to induce the formation of the DMPO/hemoglobin thiyl free radical adduct in vivo, whereas able phenelzine and hydralazine were able to form this adduct in vitro. We were able to decrease the in vivo iproniazid- induced adduct formation by pretreating the rats with bis-para- nitrophenylphosphate, an arylamidase inhibitor. Our results support the idea that iproniazid is hydrolyzed in the liver to a more reactive metabolite, most likely isopropylhydrazine, which is subsequently released into the blood stream.