In controls (KHB alone), the apparent time constant (ks) of Pi exchange toward ATP as measured by ST was 0.48 卤 0.04 s鈭? leading to a total ATP synthesis rate of 37 卤 3.9 渭mol min鈭? g鈭?. KHB + RSV perfusion increased ks (+52%; p = 0.0009 vs. KHB) leading to an enhanced rate of total ATP synthesis (+52%; p = 0.01 vs. KHB). When glycolysis was previously inhibited in KHB, both ks and ATP synthesis flux dramatically decreased (鈭?7% and 鈭?6%, respectively, p < 0.0001 vs. KHB without inhibition), evidencing a collapse of Pi-to-ATP exchange. However, glycolysis inhibition in KHB + RSV reduced to less extent ks (鈭?1%, p = 0.0005 vs. KHB + RSV without inhibition) and ATP synthesis flux (鈭?8%). Using the CI method in KHB and KHB + RSV, KCN addition after glycolysis inhibition induced a rapid fall to zero of the ATP content. The mitochondrial ATP turnover R(t0) and its time constant kd mito were similar in KHB (1.18 卤 0.19 渭mol min鈭? g鈭? and 0.91 卤 0.13 min鈭?) and KHB + RSV (1.36 卤 0.26 渭mol min鈭? g鈭? and 0.77 卤 0.18 min鈭?).
Since mitochondrial ATP turnover was not increased by RSV, the stimulation of Pi-to-ATP exchange by RSV mainly reflected an increase in glycolytic ATP synthesis flux. Moreover, the maintenance by RSV of a high level of Pi-to-ATP exchange after glycolysis inhibition evidenced a protective effect of the polyphenol, in agreement with our previous hypothesis of a stimulation of substrate flux throughout the glycolysis 3-carbon step.