Measurement of unidirectional P(i)-->ATP flux in lamb myocardium in vivo.
Measurement of unidirectional P(i)-->ATP flux in lamb myocardium in vivo.
复制标题
体内羔羊心肌单向 P(i)-->ATP 通量的测量。
DOI：
10.1016/0005-2728(94)90213-5
复制
发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Portman,MA
中科院分区：
文献类型：
--
作者：
Portman,MA
使用 31 P 磁化转移技术在有氧功能的完整绵羊心脏 (n= 5) 中研究单向心肌 ATP 合成（Pi→ ATP 通量）。心肌耗氧量 (MVO) 表示为氧原子微摩尔数/克/分钟，通过对绵羊 (n = 23) 数据的线性回归分析进行估计，绵羊在肾上腺素诱导的工作负荷分级递增过程中进行了连续 MVO 测量。在饱和转移实验期间，以每分钟 1 μg/kg 的剂量开始注入肾上腺素，以实现更高的稳态工作负荷和 MVO 水平。研究发现，随着心率压力乘积和 MVO 的增加，单向 Pi→ ATP 通量显着增加 (P< 0.05)。这些数据表明，单向 Pi→ ATP 通量至少比这些实验中通过氧化磷酸化实现的峰值 ATP 合成率高出 3 倍，并且比通过糖酵解实现的峰值 ATP 合成率高出一个数量级以上。因此，通过糖酵解的正向 Pi→ ATP 通量是测量的 Pi→ ATP 通量的主要贡献者，并且这些产生 ATP 的双向糖酵解反应处于接近平衡状态。此外，肾上腺素输注过程中引起的 ΔPi→ ATP/ΔMVO，2.70 ± 0.29 (S.E.) 与经典推导的 P:O 值相似，表明单向通量的大部分变化是由于氧化磷酸化，并且在这些条件下，糖酵解接近平衡的干扰最小。
Unidirectional myocardial ATP synthesis, Pi→ ATP flux, was studied in vivo using31P magnetization transfer techniques in intact sheep hearts (n= 5) which were functioning aerobically. Myocardial oxygen consumption (MVO) expressed as μmoles of oxygen atoms/gm/min was estimated using linear regression analysis of data derived from sheep (n= 23), which had undergone continuous MVO measurement during graded stepups in epinephrine induced work loads. During the saturation transfer experiment, epinephrine, beginning at 1 μg/kg per min was infused to achieve a higher steady-state work load and level of MVO. The unidirectional Pi→ ATP flux was found to increase significantly (P< 0.05) during increases in rate pressure product and MVO. These data show that the unidirectional Pi→ ATP flux is at least 3-times higher than the peak ATP synthesis rate, achieved through oxidative phosphorylation in these experiments, and more than a magnitude higher than the peak ATP synthesis rate through glycolysis. Therefore, forward Pi→ ATP flux through glycolysis is the major contributor to the measured Pi→ ATP flux and these ATP producing bidirectional glycolytic reactions are in a near equilibrium state. Furthermore,ΔPi→ ATP/ΔMVO, 2.70 ± 0.29 (S.E.) elicited during epinephrine infusion is similar to classically derived P:O values, indicating that most of the change in unidirectional flux is due to oxidative phosphorylation and that minimal disturbance in the glycolytic near equilibrium occurs under these conditions.