METABOLIC-FATE OF EXTRACTED GLUCOSE IN NORMAL HUMAN MYOCARDIUM
METABOLIC-FATE OF EXTRACTED GLUCOSE IN NORMAL HUMAN MYOCARDIUM
复制标题
DOI：
10.1172/jci112174
复制
发表时间：
1985-01-01
影响因子：
15.9
通讯作者：
CRAIG, JC
中科院分区：
文献类型：
--
作者：
WISNESKI, JA;GERTZ, EW;CRAIG, JC
葡萄糖是心肌代谢的重要底物。本研究旨在确定循环代谢底物对心肌葡萄糖提取的影响，并确定葡萄糖在正常人心肌中的代谢去向。23名健康男性志愿者放置冠状静脉窦和动脉导管。在10名受试者中输入[6-14C]葡萄糖作为示踪剂。其余13名受试者同时输注[6-14C]葡萄糖和[U-13C]乳酸。同时采集血液样本，用于葡萄糖、乳酸和游离脂肪酸的化学分析以及葡萄糖和乳酸的同位素分析。通过测量心肌产生14CO2来评估葡萄糖氧化。心肌摄取和氧化葡萄糖的量与动脉血游离脂肪酸水平呈负相关(r=-0.71；P<；0.0001)。20%(范围0-63%)的葡萄糖提取液立即氧化。化学乳酸分析显示净萃取率为26.0。+-。16.4%。然而，同位素分析表明，乳酸是由心肌释放的。在接受双碳标记同位素的13名受试者中，乳酸的释放量为0.09+-。0.04微克/毫升和49.5微克/毫升。其中29.5%的乳酸来自外源葡萄糖。这项研究表明，循环中游离脂肪酸的水平在决定正常人心肌提取和氧化的葡萄糖量方面起着重要作用。只有20.1.+-。提取的葡萄糖有19.4%发生氧化反应，13.0%为+-。提取的葡萄糖有9.0%被心肌代谢为乳酸并释放。因此，正常心肌提取的葡萄糖的60%-70%可能在空腹静息状态下以糖原的形式储存。
Glucose is an important substrate for myocardial metabolism. This study was designed to determine the effect of circulating metabolic substrates on myocardial glucose extraction and to determine the metabolic fate of glucose in normal human myocardium. Coronary sinus and arterial catheters were placed in 23 healthy male volunteers. [6-14C]Glucose was infused as a tracer in 10 subjects. [6-14C]Glucose and [U-13C]lactate were simultaneously infused in the other 13 subjects. Simultaneous blood samples were obtained for chemical analyses of glucose, lactate, and free fatty acids and for the isotopic analyses of glucose and lactate. Glucose oxidation was assessed by measuring myocardial 14CO2 production. The amount of glucose extracted and oxidized by the myocardium was inversely correlated with the arterial level of free fatty acids (r = -0.71; P < 0.0001). 20% (range, 0-63%) of the glucose extraction underwent immediate oxidation. Chemical lactate analysis showed a net extraction of 26.0 .+-. 16.4%. However, isotopic analysis demonstrated that lactate was being released by the myocardium. In the 13 subjects receiving the dual-carbon-labeled isotopes, the lactate released was 0.09 .+-. 0.04 .mu.mol/ml and 49.5 .+-. 29.5% of this lactate was from exogenous glucose. This study demonstrates that the circulating level of free fatty acids plays a major role in determining the amount of glucose extracted and oxidized by the normal human myocardium. Only 20.1 .+-. 19.4% of the glucose extracted underwent oxidation, and 13.0 .+-. 9.0% of the glucose extracted was metabolized to lactate and released by the myocardium. Thus, 60-70% of the glucose extracted by the normal myocardium is probably stored as glycogen in the fasting, resting state.