[Nucleotide metabolism in remnant rat liver after major hepatic resection]

Major hepatic resection is restricted in the presence of cirrhosis, because the cirrhotic liver is less able to regenerate. In the present study, to clarify what factors play a major role as inhibitors of the regeneration process, we focused on the changes in liver purine nucleotides and their catabolite levels in rats with cirrhosis. Decreases in adenine nucleotides and guanine nucleotides were observed after resection both in normal and thioacetamide-induced cirrhotic livers. These were prolonged in rats with cirrhosis. Tissue levels of hypoxanthine and xanthine increased both in the control group and in the cirrhotic group. The increase in xanthine level was remarkable in the cirrhotic group compared with the control group. These results indicate that xanthine oxidase activity is increased in cirrhotic liver after major hepatic resection. Xanthine oxidase catalyzes the oxidation of hypoxanthine to xanthine and xanthine to uric acid. Xanthine and uric acid are end metabolites of purine nucleotides. On the other hand, superoxide is generated in association with this reaction. Therefore, the disturbance in the energy metabolism and the increase in superoxide formation which are caused by the activation of xanthine oxidase might be involved in the regeneration process as inhibitory factors in cirrhotic rat liver.