Kinetic analysis of anaerobic metabolism in rats during acute cyanide poisoning

In order to investigate the changes in energy metabolism during acute anoxia, blood levels of various metabolites were analysed in cyanide-poisoned rats. After intraperitoneal injection of a sublethal dose of potassium cyanide (5 mg/kg), blood samples were obtained by cervical dislocation at intervals of 5 min until 30 min. Lactate and lactate/pyruvate ratio (L/P) in plasma concomitantly changed with cyanide; increased rapidly at 5 min, remained fairly constant until 20 min and then began to decrease at 25 min. In contrast, the products of ATP degradation, oxypurines and inorganic phosphate (Pi), increased gradually until 25 min and then began to decrease at 30 min. Allantoin in plasma scarcely increased throughout the experiments. The results indicate that the rapid activation of anaerobic ATP formation by glycolysis was followed by the increase in ATP degradation in cyanide-poisoned rats, Thus, increase in plasma oxypurines could be regarded as an indicator for severe anoxic states in tissues with massive ATP degradation.