TRICARBOXYLIC-ACID CYCLE METABOLITES DURING ISCHEMIA IN ISOLATED PERFUSED RAT-HEART
TRICARBOXYLIC-ACID CYCLE METABOLITES DURING ISCHEMIA IN ISOLATED PERFUSED RAT-HEART
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DOI：
10.1152/ajpheart.1983.244.2.h281
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发表时间：
1983-01-01
影响因子：
--
通讯作者：
HASSINEN, IE
中科院分区：
文献类型：
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作者：
PEUHKURINEN, KJ;TAKALA, TES;HASSINEN, IE
分离的大鼠心脏，在通过兰登多夫程序逆行灌流后，通过将主动脉压降至零而呈现缺血。测定了蛋白质降解速率和三羧酸循环代谢物、相关氨基酸、氨和腺嘌呤核苷酸分解产物的浓度变化的时间模式。氨基酸代谢的最大变化是蛋白水解率降低到1/10，丙氨酸大量积累，这与天冬氨酸和天冬酰胺的降解几乎是化学平衡的。与天冬氨酸和丙氨酸的代谢净通量相比，苹果酸和琥珀酸的积累较小。代谢平衡表显示天冬氨酸被转化为丙氨酸。要做到这一点，前提条件是将天冬氨酸的碳加入到三羧酸循环中，如草乙酸酯，逆转苹果酸脱氢酶，并通过苹果酸酶反应产生丙酮酸。在缺血期间积累的丙氨酸不是糖酵解的来源，而是通过逆转录反应和三羧酸循环代谢产物的协同作用而发生的。显然，在缺血心肌中，富马酸转化为琥珀酸的潜在能量产出减少并不显著。
Isolated rat hearts were, after a retrograde perfusion by the Langendorff procedure, rendered ischemic by lowering the aortic pressure to zero. The rate of proteolysis and temporal patterns of the changes in the concentrations of the metabolites of the tricarboxylic acid cycle, related amino acids, ammonia and breakdown products of the adenine nucleotides were determined. The most significant change in the amino acid metabolism was a decrease of the proteolysis to 1/10 and a large accumulation of alanine, which was almost stoichometric to the degradation of aspartate plus asparagine. The accumulation of malate and succinate was small compared with the metabolic net fluxes of aspartate and alanine. The metabolic balance sheet suggests that asparate was converted to alanine. A prerequisite for this would be a feed in a of carbon of asparate to the tricarboxylic acid cycle as oxalacetate, reversal of the malate dehydrogenase and production of pyruvate by the malic enzyme reaction. Alanine accumulating during ischemia is not glycolytic in origin but occurs through a concerted operation of anaplerotic reactions and tricarboxylic acid cycle metabolite disposal. Apparently, the potentially energy yielding reduction of fumarate to succinate is not significant in the ischemic myocardium.