LACTATE-FATTY ACID COMPETITION IN THE HEART DURING SHOCK

Abstract

The myocardium is the most versatile tissue capable of oxidizing a variety of substrates. Although free fatty acid (FFA) serves as the major metabolites under physiologic conditions in the postabsorptive state, other metabolites may replace FFA as energy yielding substrates under certain conditions. This chapter presents a study that demonstrated that elevated arterial ketone body concentration may depress myocardial FFA oxidation and increase the utilization of these substrates by the heart. The chapter discusses the answers of the following two questions that were obtained from the study: (1) the first question is whether there is an early metabolic alteration in the myocardium evident following the administration of E.coli endotoxin as the impairment of myocardial function was demonstrated 3–4 hours following endotoxin administration and as endotoxin is known to cause marked elevation of arterial lactate concentration, and (2) the second question is whether arterial lactate elevation alone without the administration of endotoxin can simulate these changes of myocardial metabolism if there is an early metabolic alteration in the myocardium evident following the administration of E.coli endotoxin..