Changes in tissue levels of carnitine during E. coli sepsis in the rat

Carnitine metabolism was studied in rats that were injected i.v. with 8 X 10(7) live colonies of E. coli per 100 g body weight or physiological saline. All rats were fasted after injection to equalize differences in food intake. Twenty-two hours following E. coli injection serum total carnitine, free carnitine, and acyl carnitine of septic rats increased by 53%, 74%, and 40% respectively, compared with the levels of the control rats. The elevated serum carnitine does not appear to be due to increased mobilization from the skeletal muscle as there were no changes in the total carnitine content of the gastrocnemius muscle during sepsis. Urinary excretion of total carnitine decreased by 62% in the septic rats compared with their controls which may account, in part, for the high serum levels of carnitine in the septic rat. There were no significant differences in the carnitine content of the livers from the septic and control rats. The acid-soluble and acid-insoluble carnitine content of the hearts from the septic rats decreased by 35% and 27%, respectively compared with the hearts from the control rats. The reduced myocardial carnitine occurs in spite of the elevated levels of serum carnitine which suggests that the rates of carnitine transport may be altered in the hearts from septic rats.