Hamat R B, Wolman S L, Fields A L, Sonnenberg K L, Cheema-Dhadli S, Halperin M L
Metabolism. 1982 Jun;31(6):548-52. doi: 10.1016/0026-0495(82)90093-2.
An "in vitro" model of one type of lactic acidosis was produced in rat hemi-diaphragms with inhibitors of pyruvate oxidation. In order to obtain this inhibition in the absence of hypoxia, two actions were sought; inhibiting the mitochondrial pyruvate transporter and lowering the rate of pyruvate diffusion into these mitochondria. alpha-Cyano-3-hydroxy cinnamate (CNCM) was utilized because it is a specific inhibitor of the mitochondrial pyruvate transporter. Aminooxyacetate (AOA) was employed because it leads indirectly to inhibition of the entry of cytoplasmic reducing power into mitochondria. As a result of the addition of this latter compound, pyruvate levels fell and this should decrease the rate of pyruvate diffusion into the mitochondria. Glucose was the only substrate provided to this tissue and its entry into the cells was promoted by insulin. The oxidation of U-14C glucose to 14CO2 was significantly reduced in the presence of CNCM and AOA, presumably reflecting the inhibition of pyruvate oxidation. Under these conditions, lactate accumulated and pyruvate fell; however, there was a significant accumulation of lactate plus pyruvate during the incubation period. This "in vitro" lactic acidosis was markedly diminished when acetate was also present. These results are consistent with the hypothesis that provision of an alternate substrate to the TCA cycle for ATP synthesis could lead to a decreased rate of glycolysis and thereby to a decreased rate of lactic acid accumulation in this "in vitro" model of lactic acidosis.
用丙酮酸氧化抑制剂在大鼠半膈肌中建立了一种“体外”乳酸酸中毒模型。为了在无缺氧情况下实现这种抑制，采取了两种措施：抑制线粒体丙酮酸转运体以及降低丙酮酸扩散进入这些线粒体的速率。使用α-氰基-3-羟基肉桂酸酯（CNCM），因为它是线粒体丙酮酸转运体的特异性抑制剂。使用氨基氧乙酸（AOA），因为它间接导致细胞质还原力进入线粒体受到抑制。由于添加了后一种化合物，丙酮酸水平下降，这应该会降低丙酮酸扩散进入线粒体的速率。葡萄糖是提供给该组织的唯一底物，胰岛素促进其进入细胞。在CNCM和AOA存在的情况下，U-14C葡萄糖氧化为14CO2的过程显著减少，推测这反映了丙酮酸氧化受到抑制。在这些条件下，乳酸积累而丙酮酸下降；然而，在孵育期间乳酸加丙酮酸有显著积累。当也存在乙酸盐时，这种“体外”乳酸酸中毒明显减轻。这些结果与以下假设一致，即在这种“体外”乳酸酸中毒模型中，为三羧酸循环提供替代底物用于ATP合成可能导致糖酵解速率降低，从而乳酸积累速率降低。
