Fatty acid metabolism in the heart during Escherichia coli sepsis in the rat

Fatty acid metabolism was studied in fasted control, fasted Escherichia coli-treated, fed control, and fed E. coli-treated rats to find out whether the reduction in myocardial carnitine was associated with changes in oxidation and esterification of long chain fatty acids. Rats were made septic by injecting i.v. 8 X 10(7) live colonies of E. coli per 100 g body weight. Fed rats were infused intragastrically with a nutritionally adequate diet containing glucose plus fat for five days before inducing sepsis. Food was removed from the fasted rats after E. coli injection. Twenty-four hours later, the production of CO2 from 1-14C]palmitate was not altered in heart homogenates from fasted or fed E. coli-treated rats. In comparison to control rats, heart homogenates from fasted E. coli-treated rats incorporated 32% more 1-14C]palmitate into triglycerides. The heart content of triglycerides was also increased threefold during sepsis. Rates of esterification and lipid composition were not altered in the hearts from fed E. coli-treated rats. The increased rate of triglyceride synthesis in the hearts from fasted E. coli-treated rats appears to be due to a 40% higher content of glycerol 3-phosphate and 55% more activity of glycerol 3-phosphate acyltransferase. These results also suggest that the reduced content of myocardial carnitine that occurs during E. coli sepsis does not limit the availability of fatty acids for oxidation.