NAD(P)⁺ transhydrogenase (NNT) is located in the inner mitochondrial membrane and catalyzes a reversible hydride transfer between NAD(H) and NADP(H) that is coupled to proton translocation between the intermembrane space and mitochondrial matrix. NNT activity has an essential role in maintaining the NADPH supply for antioxidant defense and biosynthetic pathways. In the present report, we evaluated the effects of chemical compounds used as inhibitors of NNT over the last five decades, namely, 4-chloro-7-nitrobenzofurazan (NBD-Cl), N,N′-dicyclohexylcarbodiimide (DCC), palmitoyl-CoA, palmitoyl-l-carnitine, and rhein, on NNT activity and mitochondrial respiratory function. Concentrations of these compounds that partially inhibited the forward and reverse NNT reactions in detergent-solubilized mouse liver mitochondria significantly impaired mitochondrial respiratory function, as estimated by ADP-stimulated and nonphosphorylating respiration. Among the tested compounds, NBD-Cl showed the best relationship between NNT inhibition and low impact on respiratory function. Despite this, NBD-Cl concentrations that partially inhibited NNT activity impaired mitochondrial respiratory function and significantly decreased the viability of cultured Nnt^−/− mouse astrocytes. We conclude that even though the tested compounds indeed presented inhibitory effects on NNT activity, at effective concentrations, they cause important undesirable effects on mitochondrial respiratory function and cell viability.

NAD（P）⁺转氢酶（NNT）位于线粒体内膜中，催化NAD（H）和NADP（H）之间的可逆氢化物转移，该转移与质子在膜空间和线粒体基质之间的移位有关。NNT活性在维持NADPH的供应以维持抗氧化剂防御和生物合成途径中起着至关重要的作用。在本报告中，我们评估了近五十年来用作NNT抑制剂的化合物的作用，即4-氯-7-硝基苯并呋喃山（NBD-Cl），N，N'-二环己基碳二亚胺（DCC），棕榈酰-辅酶A，棕榈升肉碱和大黄酸对NNT活性和线粒体呼吸功能的影响。通过ADP刺激的和非磷酸化的呼吸作用估计，这些在洗涤剂溶解的小鼠肝线粒体中部分抑制正向和反向NNT反应的化合物的浓度显着损害了线粒体的呼吸功能。在测试的化合物中，NBD-Cl显示出NNT抑制与对呼吸功能的低影响之间的最佳关系。尽管如此，部分抑制NNT活性的NBD-Cl浓度会损害线粒体呼吸功能，并显着降低培养的Nnt ^-/-的活力。小鼠星形胶质细胞。我们得出的结论是，即使受试化合物确实对NNT活性表现出抑制作用，但在有效浓度下，它们也会对线粒体呼吸功能和细胞活力造成重要的不良影响。