Krützfeldt A, Spahr R, Mertens S, Siegmund B, Piper H M
Physiologisches Institut I, Universität Düsseldorf, FRG.
J Mol Cell Cardiol. 1990 Dec;22(12):1393-404. doi: 10.1016/0022-2828(90)90984-a.
The ability of coronary endothelial cells in 14 day confluent cultures to metabolize glucose, palmitate, lactate and various amino acids was investigated. Under aerobic conditions, 99% of glucose, (5 mM) was degraded to lactate and only 0.04% was oxidized in the Krebs cycle. One percent of the glucose catabolized was directed into the hexose monophosphate pathway, but this fraction could be increased by 81% by 0.4 mM methylene blue. Glucose oxidation in the Krebs cycle was increased at glucose concentrations lower than 1 mM, or by the uncoupler 2,4-dinitrophenol. Oxidation to CO2 of palmitate (300 microM), lactate (1 mM), and glutamine (0.5 mM) was diminished in the presence of glucose (5 mM) by 80, 66, and 48%, respectively. These results demonstrate that coronary endothelial cells utilize exogenous glucose, at physiological concentration, predominantly for glycolytic energy production. The metabolic pattern is characteristic of the Crabtree effect. In these cells, glucose not only effectively suppresses the oxidation of the substrates lactate and palmitate, i.e. of substrates preferred by the whole heart, but also of glutamine, which is a major oxidative substrate for coronary endothelial cells. Absolute rates of substrate catabolism are low as compared to those of the beating heart indicating a low energy demand of coronary endothelial cells.
研究了14天汇合培养的冠状动脉内皮细胞代谢葡萄糖、棕榈酸酯、乳酸和各种氨基酸的能力。在有氧条件下，99%的葡萄糖（5 mM）降解为乳酸，只有0.04%在三羧酸循环中被氧化。被分解代谢的葡萄糖中有1%进入磷酸己糖途径，但0.4 mM亚甲蓝可使这一比例增加81%。当葡萄糖浓度低于1 mM或使用解偶联剂2,4-二硝基苯酚时，三羧酸循环中的葡萄糖氧化增加。在存在葡萄糖（5 mM）的情况下，棕榈酸酯（300 microM）、乳酸（1 mM）和谷氨酰胺（0.5 mM）氧化为CO2的量分别减少了80%、66%和48%。这些结果表明，冠状动脉内皮细胞在生理浓度下主要利用外源性葡萄糖进行糖酵解产生能量。这种代谢模式是克赖特效应的特征。在这些细胞中，葡萄糖不仅有效地抑制了底物乳酸和棕榈酸酯的氧化，即整个心脏偏好的底物的氧化，还抑制了谷氨酰胺的氧化，而谷氨酰胺是冠状动脉内皮细胞的主要氧化底物。与跳动的心脏相比，底物分解代谢的绝对速率较低，这表明冠状动脉内皮细胞的能量需求较低。
