Influence of Escherichia coli endotoxin on palmitate, glucose, and lactate utilization by isolated dog heart myocytes.

The in vitro effects of E. coli 0127:B8 endotoxin on the oxidation of palmitate, glucose, and lactate by isolated, beating, adult dog heart myocytes were studied. The result were correlated with the in vitro effect of endotoxin on the transport of palmitate and glucose by using their respective analog, hexadecanol and 3-O-methyl-D-glucose. Endotoxin decreased palmitate but increased glucose and lactate oxidation in a dose-dependent manner. The changes in palmitate and lactate oxidation induced by endotoxin could not be corrected by addition of L-carnitine to the reaction mixture. The transport of hexadecanol or of 3-O-methyl-D-glucose was not affected by endotoxin. These results suggest that the endotoxin-induced alteration in palmitate and glucose oxidation by the heart is not the result of an impairment in metabolite transport, but rather a defect in the subsequent intracellular oxidative processes.