A role of cytoplasmic free adenosine diphosphate in regenerating rabbit liver

Cytosolic free adenosine diphosphate (ADP) concentration in remnant rabbit liver 24 hours after 70% hepatectomy was calculated from the measured components of the glyceraldehyde-3-phosphate dehydrogenase:3-phosphoglycerate kinase/lactate dehydrogenase reaction. The concentration of free cytoplasmic ADP of the remnant liver increased from the control value of 76.9 +/- 6.0 mumol/L to 208.8 +/- 31.9 mumol/L (mean +/- SEM) at 24 hours after hepatectomy. The calculated free ADP provides the following three interpretations with respect to mitochondrial respiration acceleration as a result of liver regeneration. First, the Michaelis-Menten equation for physiologic respiration relative to maximal respiration gave 1.16 as the value of acceleration. Next, the classical thermodynamic theory showed that the logarithm of [adenosine triphosphate]/[free ADP] [free inorganic phosphate], which is reciprocally correlated with mitochondrial respiration, was decreased by a factor of 0.78 after hepatectomy. Finally, the irreversible thermodynamic theory indicated that chemical affinity, which is linearly correlated to mitochondrial respiration, was increased 1.36 times. These interpretations suggest that the rate of mitochondrial respiration is accelerated after major hepatectomy.