Fluorometric Determination of 1,2,3,4-Tetrahydro-6,7-dihydroxyisoquinoline in Biological Materials by HPLC.
作者:Akira SHIRAHATA、Masanori YOSHIOKA、Zenzo TAMURA
DOI:10.1248/cpb.45.1814
日期:——
In the belief that endogenous 1, 2, 3, 4-tetrahydro-6, 7-dihydroxyisoquinoline (DA-Fp) could be a potential marker involved in the etiology of various diseases such as Parkinsonism, we attempted to develop a fluorescence method for DA-Fp. It was synthesized by condensation of dopamine with formaldehyde according to an established method.Periodate was identified by screening from various oxidation reagents as a fluorescence reagent to DA-Fp. Optimal reaction conditions were obtained with 0.25 mM NaIO4 in 0.1 M phosphate buffer (pH 8.0) at 37°C for 15 min. The fluorescence spectrum of the derivative showed that we had found a new reaction specific for DA-Fp. This reaction we coupled on-line to high performance liquid chromatography (HPLC), which enabled us to achieve a highly sensitive method for determining DA-Fp. A working curve was linear from 2 to 800 pmol of DA-Fp per injection.To determine DA-Fp in biological materials, the pretreatment before HPLC was optimized by hydrolysis of its conjugate and suppression of the artifact with l-phenylephrine. Urinary excretion of DA-Fp in men was measured by this new present method. The urinary excretion of endogenous DA-Fp increased in a rabbit given L-DOPA. The DA-Fp concentration was determined in rat brain. The significance of DA-Fp in these biological materials is discussed and evaluated. We conclude that the present method will be useful for studying tetrahydroisoquinolines involved in meny diseases.
由于认为内源性 1, 2, 3, 4-四氢-6, 7-二羟基异喹啉(DA-Fp)可能是帕金森病等多种疾病病因的潜在标志物,我们尝试开发一种 DA-Fp 的荧光方法。通过从各种氧化试剂中筛选,确定高碘酸盐为 DA-Fp 的荧光试剂。最佳反应条件是在 0.1 M 磷酸盐缓冲液(pH 8.0)中加入 0.25 mM NaIO4,在 37°C 下反应 15 分钟。衍生物的荧光光谱显示,我们发现了 DA-Fp 的新特异性反应。我们将该反应与高效液相色谱(HPLC)联用,从而实现了高灵敏度的 DA-Fp 检测方法。为了测定生物材料中的DA-Fp,我们对HPLC前的预处理进行了优化,水解了DA-Fp的共轭物,并用l-苯肾上腺素抑制了伪影。采用这种新方法测定了男性尿液中DA-Fp的排泄量。服用 L-DOPA 的兔子尿液中内源性 DA-Fp 的排泄量增加。测定了大鼠大脑中的 DA-Fp 浓度。我们讨论并评估了 DA-Fp 在这些生物材料中的意义。我们得出结论,本方法将有助于研究与多种疾病相关的四氢异喹啉类化合物。