Relation among regional O2 consumption, high-energy phosphates, and substrate uptake in porcine right ventricle.
Relation among regional O2 consumption, high-energy phosphates, and substrate uptake in porcine right ventricle.
复制标题
猪右心室区域 O2 消耗、高能磷酸盐和底物吸收之间的关系。
DOI：
10.1152/ajpheart.1994.266.2.h521
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Steinman,S
中科院分区：
文献类型：
--
作者：
Schwartz,GG;Greyson,CR;Wisneski,JA;Garcia,J;Steinman,S
磷酸盐代谢物的变化可能在体内心肌氧化磷酸化的调节中发挥作用。我们测试了以下假设：随着心肌耗氧量 (MVO2) 增加，磷酸盐代谢物的变化取决于 MVO2 增加的机制。在 17 只开胸猪中，通过异丙肾上腺素输注 (Iso) 和肺动脉收缩 (PAC)，右心室 (RV) 游离壁的局部 MVO2 较对照有所增加。磷酸肌酸与 ATP 的比率 (PCr/ATP) 与游离 ADP 浓度 ([ADP]) 成反比，通过 31P 核磁共振 (NMR) 光谱测定。在 NMR 线圈正下方的心肌中测定区域 MVO2 和乳酸、葡萄糖和游离脂肪酸 (FFA) 的摄取。 Iso 和 PAC 几乎同等地增加了 MVO2，大约达到对照的两倍，但产生了相反方向的 PCr/ATP 变化：PAC 显着降低（对照 1.52 +/- 0.06，PAC 1.35 +/- 0.06，意味着 +/- SE），但 Iso 显着增加（至 1.72 +/- 0.07）。因此，[ADP] 的增加可能在 PAC 期间刺激了氧化磷酸化，但在 Iso 期间则不会。使用 Iso，FFA 的吸收量是 PAC 的三倍以上，乳酸、葡萄糖和 FFA 的氧提取率之和是 PAC 的两倍以上。 Iso 期间增强的底物摄取可能增加了线粒体 NADH，这反过来可能为氧化磷酸化速率提供了替代刺激。这些结果支持体内 RV 氧化磷酸化的多因素控制。
Changes in phosphate metabolites may play a role in the regulation of myocardial oxidative phosphorylation in vivo. We tested the hypothesis that changes in phosphate metabolites with increased myocardial oxygen consumption (MVO2) depend on the mechanism by which MVO2 is increased. In 17 open-chest pigs, regional MVO2 of the right ventricular (RV) free wall was increased from control by isoproterenol infusion (Iso) and by pulmonary artery constriction (PAC). The phosphocreatine-to-ATP ratio (PCr/ATP), which is inversely related to free ADP concentration ([ADP]), was determined by 31P-nuclear magnetic resonance (NMR) spectroscopy. Regional MVO2 and lactate, glucose, and free fatty acid (FFA) uptake were determined in the myocardium directly beneath the NMR coil. Iso and PAC increased MVO2 nearly equally, to approximately twice control, but produced directionally opposite changes in PCr/ATP: a significant decrease with PAC (control 1.52 +/- 0.06, PAC 1.35 +/- 0.06, means +/- SE) but a significant increase with Iso (to 1.72 +/- 0.07). Thus increased [ADP] may have stimulated oxidative phosphorylation during PAC but could not have done so during Iso. With Iso, uptake of FFA was more than three times that with PAC, and the sum of the oxygen extraction ratios for lactate, glucose, and FFA was more than double that with PAC. Enhanced substrate uptake during Iso may have increased mitochondrial NADH, which in turn may have provided an alternative stimulus to the rate of oxidative phosphorylation. These results support multifactorial control of RV oxidative phosphorylation in vivo.