The metabolic state of the rat liver in vivo measured by 31P-NMR spectroscopy.
The metabolic state of the rat liver in vivo measured by 31P-NMR spectroscopy.
复制标题
通过 31P-NMR 光谱测量大鼠肝脏的体内代谢状态。
DOI：
10.1016/0167-4889(86)90032-7
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Radda,GK
中科院分区：
文献类型：
--
作者：
Malloy,CR;Cunningham,CC;Radda,GK
以前的31P核磁共振研究通过酶催化的反应测量了各种组织中磷酸盐、游离镁离子、pH和通量的浓度。已研制出一种外科植入的线圈，用于在活体内测量大鼠肝脏的这些参数，并评估外部扰动对肝脏中磷代谢产物浓度和生理环境的影响。确定了线圈的敏感体积和最佳脉冲，并对线圈进行了绝缘，以排除来自周围组织的信号。在核磁共振实验完成后立即冷冻夹住的肝脏中，[PI]、[ATP]、[乳酸]和[丙酮酸]的正常值证明了在获取光谱期间肝脏的代谢稳定性。细胞内pH(7.2)、游离[Mg2+](0.7 mM)和核磁共振可检测的[PI][ATP]的恒定值也证实了其稳定性。通过比较饲养和禁食48h大鼠的31P-核磁共振谱，说明了活体肝脏31P-核磁共振谱对动物生理状态的敏感性。主要的质量差异是吡啶核苷酸/腺嘌呤核苷酸比率的增加，以及复合单酯峰频率的微小但一致的移动。用改进的Homospoil饱和恢复脉冲序列在体内测量了各主要磷酸盐共振的自旋-晶格弛豫时间，三磷酸腺苷γ-磷酸盐的T1为0.17 S，选择饱和实验没有检测到γ-磷酸盐与无机磷酸盐之间的磁化转移。
Previous 31 P nuclear magnetic resonance (NMR) studies have measured the concentrations of phosphates, free Mg 2+, pH and flux through enzyme-catalyzed reactions in a variety of tissues. A surgically-implanted coil has been developed to measure these parameters in the rat liver in vivo, and to assess the effect of external perturbations on the concentrations and physiological environment of phosphorus metabolites in the liver. The sensitive volume and optimal pulse were determined for the coil, which was insulated to exclude signal from surrounding tissues. The metabolic stability of the liver during acquisition of spectra was demonstrated by normal values for [P i],[ATP],[lactate], and [pyruvate] in livers which were freeze-clamped immediately after completion of the NMR experiment. The stability was also confirmed by constant values for intracellular pH (7.2), free [Mg 2+](0.7 mM), and NMR detectable [P i][ATP]. The sensitivity of the 31 P-NMR spectrum of the liver in vivo to the physiological state of the animals was illustrated by comparing spectra from fed and 48 h fasted rats. The major qualitative differences were an increase in the pyridine nucleotide/adenine nucleotide ratio, and a small, but consistent shift in the frequency of the composite phosphomonoester peak. The spin-lattice relaxation time of each major phosphate resonance was measured in vivo using a modified homospoil saturation recovery pulse sequence; the T 1 of ATP γ-phosphate was 0.17 s. Selective saturation experiments did not detect magnetization transfer between the ATP γ-phosphate and inorganic phosphate.