Arterial ketone index in assessing liver function and its detoxicative capability after ischemia-reperfusion injury

Arterial ketone index (AKBR) which is the ratio of acetoacetic acid to 3-hydroxybutyric acid in the arterial blood, is believed to reflect the mitochondrial reduction potential of hepatocytes and general energy state of the liver. In the presented paper we challenged this hypothesis by analysing the correlation between AKBR and the results of typical liver blood tests (AspAT, AlAT, LDH, CRP) and biotransforming potential of the liver (cytochromes P450, b5 and their corresponding NADPH and NADH reductases) in the model of ischemia-reperfusion injury of rat liver. The results were compared with histochemical analysis of distribution and activity of SDH, LDH and G-6-Pase, the key marker enzymes of the liver. We have shown that, except in the case of acute phase protein (CRP), a decrease in AKBR correlated well with the increase of the level of indicator enzymes in serum. Histochemical analysis also confirmed that AKBR correlates with the degree of damage to hepatocytes during early stage of reperfusion after 60 min of liver ischemia. In the Spearman test, AKBR was significantly correlated with the changes in cytochrome P450 content and its NADPH reductase activity which indicates a high sensitivity of this test. We conclude that the decrease of AKBR value reflects the impairment of basic energy pathways and detoxicative capability of the liver.