Myocardial substrate utilization in dogs following endotoxin administration.

SPITZER,JOHN J.,A.A. BECHTEL, L.T. ARCHER, M.R. BLACK, AND L. B. HINSHAW. Myocardial substrate utiliZation in dogs following endotoxin administration. Am. J. Physiol. 227(l) : 132-136. 1974.Changes of myocardial substrate utilization have been studied in dogs under pentobarbital anesthesia following the administration of E. coli endotoxin. Myocardial substrate utilization under control conditions, at 2 h, and again at 3-4 h following endotoxin administration was compared. At both periods following endotoxin, mean arterial blood pressure, heart rate, and arterial pH were decreased while myocardial blood flow did not change. Arterial lactate increased greatly, FFA did not change, and glucose and 02 decreased. Myocardial uptake and oxidation of FFA were greatly diminished and lactate uptake was markedly elevated at both periods following endotoxin. While under control conditions, more than 700/;, of the energy utilization of the myocardium was derived from FFA and about 30% was derived from lactate; following the administration of endotoxin the contribution of FFA to myocardial energy utilization was greatly diminished and that of lactate was elevated. Thus, a shift in utilization of substrates was observed favoring lactate and diminishing the contribution of FFA. These findings were similar to the changes in substrate utilization that were observed previously during experimentally produced hemorrhagic hypotension.